water and sediment ph.d
TRANSCRIPT
Hindawi Publishing CorporationISRN Soil ScienceVolume 2013 Article ID 131647 12 pageshttpdxdoiorg1011552013131647
Research ArticleOrganochlorine Pesticide Residues in Sediments and Watersfrom Cocoa Producing Areas of Ondo State SouthwesternNigeria
Aderonke Adetutu Okoya1 Aderemi Okunola Ogunfowokan2 Olabode Idowu Asubiojo2
and Nelson Torto3
1 Institute of Ecology and Environmental Studies Obafemi Awolowo University Ile-Ife Nigeria2 Department of Chemistry Obafemi Awolowo University Ile-Ife Nigeria3 Department of Chemistry Rhodes University Grahamstown 6140 South Africa
Correspondence should be addressed to Aderonke Adetutu Okoya ronkeokoyayahoocom
Received 10 January 2013 Accepted 5 February 2013
Academic Editors D Lin C Martius and D van Tuinen
Copyright copy 2013 Aderonke Adetutu Okoya et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited
This study investigated levels of organochlorine pesticide (OCP) residues in water and sediment samples from eleven rivers servingas drinking water sources and receiving runoff from nearby cocoa plantations in Ondo State Nigeria Twenty-two compositesamples of surface water and sediments (0ndash3 cm) were collected randomly using grab technique and replicated thrice per seasonThe efficiency of the two techniques [supercritical fluid extraction (SFE) and liquidliquid extraction (LLE)] was evaluated withpercentage analyte recoveries 9817 plusmn 003 to 13472 plusmn 002 for SFE and 8482 plusmn 332 to 110283 plusmn 317 for LLE Determination ofOCPs by gas chromatography with electron capture detection gave higher concentrations for sediments compared to the equivalentwater samples The commonly occurring pesticide residues in the sediments were (range 120583g gminus1) cis-chlordane 003ndash699 120572-endosulfan 003ndash699 pp1015840-DDE 008ndash1904 and dieldrin 001ndash762 in the sediments and dieldrin (not detected-151 120583g Lminus1) in watersamples during the dry season OCP levels were significantly (119875 lt 005) higher in dry season than wet season among the riversThe study concluded that most of the rivers in cocoa growing areas were contaminated with OCPs associated with agriculturalactivities
1 Introduction
In spite of the benefits (especially with respect to food pro-duction and healthmanagement) derived from the use of pes-ticides the environmental consequences of the widespreaduse handling and disposal methods of pesticides are of greatconcern [1 2] It had been reported that the constraintsduring acquisition [3] and application of pesticides in thehumid forest zones could lead to the risky handling ofobsolete pesticides which represents a threat to health andenvironment This is because their toxicity has led to thedeterioration of human health [4] especially with respect tocancer neurological damage and abnormal immune systemincluding the foetus and foetus reproductive system [5ndash8]as
well as fish kills honey bee poisonings and the contamina-tion of livestock products [9] 1
The most commonly used pesticides are the organochlo-rine pesticides and they are considered to be responsiblefor the various environmental consequences The largestregional example of pesticide contamination and humanhealth is perhaps that of the Aral sea-region in Asia [10]Human health effects of pesticides are caused by inhalationand ingestion through skin contact handling of pesticideproducts breathing of dust or spray and pesticides consumedonin food water and aquatic organisms In view of theirtoxicity to some plants and insects and persistence in theenvironment many synthetic organochlorine compoundshave found extensive use as pesticides [1 11] Pesticides usageis indeed responsible for the current ability of the developed
2 ISRN Soil Science
Table 1 Percentage recoveries retention times and response factors of the pesticide standard mixture
Standards Recovery Retention time (min) Response factorLLE SFE
HCB 9779 plusmn 113 10314 plusmn 005 831 041120572BHC 9027 plusmn 834 9959 plusmn 003 858 048120573BHC 9330 plusmn 209 9957 plusmn 001 974 056120574BHC 9858 plusmn 315 13041 plusmn 1601 952 054Heptachlor 9946 plusmn 122 9991 plusmn 002 1052 096Aldrin 9661 plusmn 148 9985 plusmn 002 1151 107Trans-Chlordane 9402 plusmn 179 13472 plusmn 002 1407 110Cis-Chlordane 9601 plusmn 196 10029 plusmn 001 1459 060120572-endosulfan 9601 plusmn 185 10029 plusmn 001 1459 060pp1015840-DDE 9448 plusmn 111 9986 plusmn 002 1541 068Dieldrin 8793 plusmn 233 9817 plusmn 003 1583 103op1015840-DDD 10283 plusmn 317 12495 plusmn 002 1638 081Endrin 9140 plusmn 353 10790 plusmn 004 1716 108pp1015840-DDD 9168 plusmn 154 11510 plusmn 003 1772 080120573-endosulfan 8482 plusmn 332 11535 plusmn 001 1812 105pp1015840-DDT 9079 plusmn 456 11589 plusmn 002 1909 086Methoxychlor (I S) 2296 mdash
Table 2 Sampling sites and their geographical position
119878119873 Sample GPS location of sampling point Local name of study unit
1 R1S107∘10101584027910158401015840N004∘51101584054221015840E Agoo river at Ile-Oluji
2 R2S207∘18101584036610158401015840N005∘39101584055310158401015840E Ose river at Ose
3 R3S307∘16101584027110158401015840N005∘9101584056910158401015840E Ala river at Akure
4 R4S407∘6101584039810158401015840N004∘49101584026710158401015840E Luwa river at Ondo
5 R5S507∘15101584035810158401015840N005∘2210158404641015840E Ogbese river at Ogbese
6 R6S607∘10101584017410158401015840N004∘431015840551015840E Oni river at IfetedoOke-Igbo
7 R7S707∘1310158405610158401015840N005∘31015840541E Aponmu river at Aponmu
8 R8S807∘1310158405610158401015840N004∘1510158400010158401015840E Osun river at Osogbo
9 R9S907∘1310158405610158401015840N004∘3010158400010158401015840E Opa river at Ile-Ife
10 R10S1007∘24101584010910158401015840N005∘00101584049510158401015840E Owena-Osun river at Owena-Ijesa
11 R11S1107∘11101584052210158401015840N005∘01101584014610158401015840E Owena-Ondo river in Ondo
countries to produce and harvest large amount of food cropson relatively small amount of landwith a relatively small inputof human labour
One major problem of cocoa growing is presented bydiseases and pests [12ndash14] Large scale spraying of pesticidesagainst these diseases has been employed by most farmers A
lot of effort has been channeled by environmental protectionagencies and organizations in developed countries towardsregulation of organochlorine pesticides use in order to pre-vent their concentrations from exceeding permissible levelsparticularly in our food supply Pesticides contamination wasalso reported in areas where citric crops are predominant by
ISRN Soil Science 3
Table3Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthew
etseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
ND
ND
004
bplusmn003555
aplusmn001002
bplusmn001016
bplusmn007006
bplusmn005011
bplusmn007013
bplusmn002
ND
NS
120572-BHC
ND
ND
ND
099
aplusmn003004
bplusmn002
ND
017
bplusmn013025
bplusmn003
ND
ND
NS
120573-BHC
ND
ND
ND
725
aplusmn001
ND
029
bplusmn013162
bplusmn077018plusmn005
bND
ND
NS
120574-BHC
ND
ND
ND
528
aplusmn001004
bplusmn001039
bplusmn017079
bplusmn006015
bplusmn001064
bplusmn053
ND
NS
Heptachlor
ND
ND
ND
116
aplusmn001
ND
ND
058
baplusmn004
001
bplusmn001109
aplusmn006
ND
NS
Aldrin
ND
ND
ND
276
aplusmn002
ND
ND
ND
ND
ND
ND
NS
Trans-chlordane174
bplusmn002
ND
001
bplusmn001458
aplusmn003
ND
ND
049
bplusmn027023
bplusmn012
ND
058
bplusmn001
NS
Cis-chlordane
ND
ND
002
bplusmn001
ND
036
bplusmn017002
bplusmn001
ND
003
bplusmn002299
aplusmn061
ND
NS
120572-end
osulfan
ND
ND
002
bplusmn001
ND
036
bplusmn007002
bplusmn001
ND
003plusmn002
b212
aplusmn019
ND
NS
120573-end
osulfan014
bplusmn007
ND
006
bplusmn002150
aplusmn001002
cplusmn001
ND
088
bplusmn002004
cplusmn002
ND
ND
NS
pp1015840-D
DE
ND
ND
006
bplusmn001791
aplusmn004151
bplusmn002037
bplusmn008501
aplusmn151013
bplusmn015035
bplusmn031
ND
NS
op1015840-D
DD
002
bplusmn001
ND
ND
518
aplusmn003
ND
ND
009
bplusmn002
001
bplusmn001
ND
ND
NS
pp1015840-D
DD
131
bplusmn008
ND
001
bplusmn0011028aplusmn001
ND
ND
148
bplusmn017013
bplusmn011
ND
ND
NS
pp1015840-D
DT
174
aplusmn001011
bplusmn000
001
bplusmn001115
bplusmn015
ND
002
bplusmn002018
bplusmn006043
bplusmn001
ND
ND
NS
Dieldrin
456
bplusmn002057
cplusmn006303
cbplusmn003882
aplusmn004099
cbplusmn053012
cplusmn006046
cplusmn003061
cplusmn011343
cbplusmn001007
cplusmn003
NS
Endrin
ND
ND
001
bplusmn001443
aplusmn004
ND
ND
032
bplusmn001012
bplusmn001
ND
ND
NS
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
4 ISRN Soil Science
Table4Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthed
ryseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
189
bplusmn005
ND
051
bplusmn0062518aplusmn305605
bplusmn002033
bplusmn012469
bplusmn153
NS
NS
ND
004
bplusmn003
120572-BHC
503
baplusmn002
ND
095
cplusmn008
001
cplusmn001232
bcplusmn153018
cplusmn003807
aplusmn300
NS
NS
ND
005
cplusmn001
120573-BHC
460
bplusmn022051
bplusmn077326
bplusmn005
001
bplusmn001010
bplusmn006131
bplusmn0061091aplusmn666
NS
NS
ND
014
bplusmn011
120574-BHC
405
bplusmn001
ND
022
bplusmn004
001
bplusmn001908
aplusmn002093
bplusmn008389
bplusmn004
NS
NS
ND
005
bplusmn001
Heptachlor
ND
bND
ND
ND
ND
ND
ND
NS
NS
ND
ND
Aldrin
655
aplusmn002
ND
003
bplusmn001
001
aplusmn001005
bplusmn003080
bplusmn037139
bplusmn005
NS
NS
ND
010
bplusmn007
Trans-chlordane264
bplusmn001
ND
380
bplusmn0038132aplusmn706026
bplusmn006047
bplusmn011288
bplusmn153
NS
NS058
bplusmn008039
bplusmn006
Cis-chlordane344
bplusmn002199
cbplusmn005020
cplusmn007106
cbplusmn003699
aplusmn005228
cbplusmn103023
cplusmn015
NS
NS103
cbplusmn100003
cplusmn001
120572-end
osulfan344
bplusmn002199
cbplusmn001020
cplusmn008106
cbplusmn003699
aplusmn002228
cbplusmn153023
cplusmn015
NS
NS103
cbplusmn071003
cplusmn001
120573-end
osulfan136
bplusmn001
ND
584
aplusmn100704
aplusmn002198
bplusmn001080
bplusmn069009
bplusmn007
NS
NS
001
bplusmn001008
bplusmn002
pp1015840-D
DE
1789aplusmn003775
bplusmn066326
bplusmn005279
bplusmn004121
bplusmn115337
bplusmn3081904aplusmn125
NS
NS008
bplusmn003019
bplusmn015
op1015840-D
DD
312
bplusmn109
ND
ND
1115aplusmn136009
bplusmn003025
bplusmn009954
aplusmn410
NS
NS
001
bplusmn001009
bplusmn007
pp1015840-D
DD
205
bplusmn001
ND
705
bplusmn0135740aplusmn676006
bplusmn005154
bplusmn136074
bplusmn016
NS
NS
001
bplusmn001008
bplusmn007
Dieldrin
238
cbplusmn001239
cbplusmn001762
aplusmn572
001
dplusmn001013
dplusmn005313
bplusmn153018
dplusmn003
NS
NS065
cdplusmn053005
dplusmn003
Endrin
114
bplusmn005
ND
022
cplusmn0162128aplusmn317011
cplusmn003039
cplusmn012054
cplusmn015
NS
NS
ND
002
cplusmn001
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
ISRN Soil Science 5
Table5Meanconcentration(120583gL)
andseason
alvaria
tionof
organo
chlorin
ecom
poun
dsin
somer
iversinOnd
oState
Analytes
Agoo-Ile
-Oluji
Ose
Ala
OLu
wa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oDry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
HCB
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120574-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Heptachlor
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Aldrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
Trans-chlordane
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
034
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
Cis-chlordane
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn009
ND
ND
ND
ND
ND
001
cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-end
osulfan
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn002
ND
ND
ND
ND
ND001cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-end
osulfan
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DE
ND
ND
ND
ND
ND
ND
011
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
opl-D
DD
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DT
ND
ND
ND
ND
ND
ND
002
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Dieldrin
ND
ND
ND
ND
107
bplusmn006
ND
151
aplusmn005
ND
ND
ND
ND
ND
ND
ND
ND025abplusmn004
ND
ND
ND
ND
ND
ND
Endrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Datainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNDnot
detected
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
2 ISRN Soil Science
Table 1 Percentage recoveries retention times and response factors of the pesticide standard mixture
Standards Recovery Retention time (min) Response factorLLE SFE
HCB 9779 plusmn 113 10314 plusmn 005 831 041120572BHC 9027 plusmn 834 9959 plusmn 003 858 048120573BHC 9330 plusmn 209 9957 plusmn 001 974 056120574BHC 9858 plusmn 315 13041 plusmn 1601 952 054Heptachlor 9946 plusmn 122 9991 plusmn 002 1052 096Aldrin 9661 plusmn 148 9985 plusmn 002 1151 107Trans-Chlordane 9402 plusmn 179 13472 plusmn 002 1407 110Cis-Chlordane 9601 plusmn 196 10029 plusmn 001 1459 060120572-endosulfan 9601 plusmn 185 10029 plusmn 001 1459 060pp1015840-DDE 9448 plusmn 111 9986 plusmn 002 1541 068Dieldrin 8793 plusmn 233 9817 plusmn 003 1583 103op1015840-DDD 10283 plusmn 317 12495 plusmn 002 1638 081Endrin 9140 plusmn 353 10790 plusmn 004 1716 108pp1015840-DDD 9168 plusmn 154 11510 plusmn 003 1772 080120573-endosulfan 8482 plusmn 332 11535 plusmn 001 1812 105pp1015840-DDT 9079 plusmn 456 11589 plusmn 002 1909 086Methoxychlor (I S) 2296 mdash
Table 2 Sampling sites and their geographical position
119878119873 Sample GPS location of sampling point Local name of study unit
1 R1S107∘10101584027910158401015840N004∘51101584054221015840E Agoo river at Ile-Oluji
2 R2S207∘18101584036610158401015840N005∘39101584055310158401015840E Ose river at Ose
3 R3S307∘16101584027110158401015840N005∘9101584056910158401015840E Ala river at Akure
4 R4S407∘6101584039810158401015840N004∘49101584026710158401015840E Luwa river at Ondo
5 R5S507∘15101584035810158401015840N005∘2210158404641015840E Ogbese river at Ogbese
6 R6S607∘10101584017410158401015840N004∘431015840551015840E Oni river at IfetedoOke-Igbo
7 R7S707∘1310158405610158401015840N005∘31015840541E Aponmu river at Aponmu
8 R8S807∘1310158405610158401015840N004∘1510158400010158401015840E Osun river at Osogbo
9 R9S907∘1310158405610158401015840N004∘3010158400010158401015840E Opa river at Ile-Ife
10 R10S1007∘24101584010910158401015840N005∘00101584049510158401015840E Owena-Osun river at Owena-Ijesa
11 R11S1107∘11101584052210158401015840N005∘01101584014610158401015840E Owena-Ondo river in Ondo
countries to produce and harvest large amount of food cropson relatively small amount of landwith a relatively small inputof human labour
One major problem of cocoa growing is presented bydiseases and pests [12ndash14] Large scale spraying of pesticidesagainst these diseases has been employed by most farmers A
lot of effort has been channeled by environmental protectionagencies and organizations in developed countries towardsregulation of organochlorine pesticides use in order to pre-vent their concentrations from exceeding permissible levelsparticularly in our food supply Pesticides contamination wasalso reported in areas where citric crops are predominant by
ISRN Soil Science 3
Table3Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthew
etseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
ND
ND
004
bplusmn003555
aplusmn001002
bplusmn001016
bplusmn007006
bplusmn005011
bplusmn007013
bplusmn002
ND
NS
120572-BHC
ND
ND
ND
099
aplusmn003004
bplusmn002
ND
017
bplusmn013025
bplusmn003
ND
ND
NS
120573-BHC
ND
ND
ND
725
aplusmn001
ND
029
bplusmn013162
bplusmn077018plusmn005
bND
ND
NS
120574-BHC
ND
ND
ND
528
aplusmn001004
bplusmn001039
bplusmn017079
bplusmn006015
bplusmn001064
bplusmn053
ND
NS
Heptachlor
ND
ND
ND
116
aplusmn001
ND
ND
058
baplusmn004
001
bplusmn001109
aplusmn006
ND
NS
Aldrin
ND
ND
ND
276
aplusmn002
ND
ND
ND
ND
ND
ND
NS
Trans-chlordane174
bplusmn002
ND
001
bplusmn001458
aplusmn003
ND
ND
049
bplusmn027023
bplusmn012
ND
058
bplusmn001
NS
Cis-chlordane
ND
ND
002
bplusmn001
ND
036
bplusmn017002
bplusmn001
ND
003
bplusmn002299
aplusmn061
ND
NS
120572-end
osulfan
ND
ND
002
bplusmn001
ND
036
bplusmn007002
bplusmn001
ND
003plusmn002
b212
aplusmn019
ND
NS
120573-end
osulfan014
bplusmn007
ND
006
bplusmn002150
aplusmn001002
cplusmn001
ND
088
bplusmn002004
cplusmn002
ND
ND
NS
pp1015840-D
DE
ND
ND
006
bplusmn001791
aplusmn004151
bplusmn002037
bplusmn008501
aplusmn151013
bplusmn015035
bplusmn031
ND
NS
op1015840-D
DD
002
bplusmn001
ND
ND
518
aplusmn003
ND
ND
009
bplusmn002
001
bplusmn001
ND
ND
NS
pp1015840-D
DD
131
bplusmn008
ND
001
bplusmn0011028aplusmn001
ND
ND
148
bplusmn017013
bplusmn011
ND
ND
NS
pp1015840-D
DT
174
aplusmn001011
bplusmn000
001
bplusmn001115
bplusmn015
ND
002
bplusmn002018
bplusmn006043
bplusmn001
ND
ND
NS
Dieldrin
456
bplusmn002057
cplusmn006303
cbplusmn003882
aplusmn004099
cbplusmn053012
cplusmn006046
cplusmn003061
cplusmn011343
cbplusmn001007
cplusmn003
NS
Endrin
ND
ND
001
bplusmn001443
aplusmn004
ND
ND
032
bplusmn001012
bplusmn001
ND
ND
NS
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
4 ISRN Soil Science
Table4Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthed
ryseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
189
bplusmn005
ND
051
bplusmn0062518aplusmn305605
bplusmn002033
bplusmn012469
bplusmn153
NS
NS
ND
004
bplusmn003
120572-BHC
503
baplusmn002
ND
095
cplusmn008
001
cplusmn001232
bcplusmn153018
cplusmn003807
aplusmn300
NS
NS
ND
005
cplusmn001
120573-BHC
460
bplusmn022051
bplusmn077326
bplusmn005
001
bplusmn001010
bplusmn006131
bplusmn0061091aplusmn666
NS
NS
ND
014
bplusmn011
120574-BHC
405
bplusmn001
ND
022
bplusmn004
001
bplusmn001908
aplusmn002093
bplusmn008389
bplusmn004
NS
NS
ND
005
bplusmn001
Heptachlor
ND
bND
ND
ND
ND
ND
ND
NS
NS
ND
ND
Aldrin
655
aplusmn002
ND
003
bplusmn001
001
aplusmn001005
bplusmn003080
bplusmn037139
bplusmn005
NS
NS
ND
010
bplusmn007
Trans-chlordane264
bplusmn001
ND
380
bplusmn0038132aplusmn706026
bplusmn006047
bplusmn011288
bplusmn153
NS
NS058
bplusmn008039
bplusmn006
Cis-chlordane344
bplusmn002199
cbplusmn005020
cplusmn007106
cbplusmn003699
aplusmn005228
cbplusmn103023
cplusmn015
NS
NS103
cbplusmn100003
cplusmn001
120572-end
osulfan344
bplusmn002199
cbplusmn001020
cplusmn008106
cbplusmn003699
aplusmn002228
cbplusmn153023
cplusmn015
NS
NS103
cbplusmn071003
cplusmn001
120573-end
osulfan136
bplusmn001
ND
584
aplusmn100704
aplusmn002198
bplusmn001080
bplusmn069009
bplusmn007
NS
NS
001
bplusmn001008
bplusmn002
pp1015840-D
DE
1789aplusmn003775
bplusmn066326
bplusmn005279
bplusmn004121
bplusmn115337
bplusmn3081904aplusmn125
NS
NS008
bplusmn003019
bplusmn015
op1015840-D
DD
312
bplusmn109
ND
ND
1115aplusmn136009
bplusmn003025
bplusmn009954
aplusmn410
NS
NS
001
bplusmn001009
bplusmn007
pp1015840-D
DD
205
bplusmn001
ND
705
bplusmn0135740aplusmn676006
bplusmn005154
bplusmn136074
bplusmn016
NS
NS
001
bplusmn001008
bplusmn007
Dieldrin
238
cbplusmn001239
cbplusmn001762
aplusmn572
001
dplusmn001013
dplusmn005313
bplusmn153018
dplusmn003
NS
NS065
cdplusmn053005
dplusmn003
Endrin
114
bplusmn005
ND
022
cplusmn0162128aplusmn317011
cplusmn003039
cplusmn012054
cplusmn015
NS
NS
ND
002
cplusmn001
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
ISRN Soil Science 5
Table5Meanconcentration(120583gL)
andseason
alvaria
tionof
organo
chlorin
ecom
poun
dsin
somer
iversinOnd
oState
Analytes
Agoo-Ile
-Oluji
Ose
Ala
OLu
wa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oDry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
HCB
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120574-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Heptachlor
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Aldrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
Trans-chlordane
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
034
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
Cis-chlordane
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn009
ND
ND
ND
ND
ND
001
cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-end
osulfan
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn002
ND
ND
ND
ND
ND001cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-end
osulfan
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DE
ND
ND
ND
ND
ND
ND
011
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
opl-D
DD
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DT
ND
ND
ND
ND
ND
ND
002
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Dieldrin
ND
ND
ND
ND
107
bplusmn006
ND
151
aplusmn005
ND
ND
ND
ND
ND
ND
ND
ND025abplusmn004
ND
ND
ND
ND
ND
ND
Endrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Datainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNDnot
detected
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
ISRN Soil Science 3
Table3Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthew
etseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
ND
ND
004
bplusmn003555
aplusmn001002
bplusmn001016
bplusmn007006
bplusmn005011
bplusmn007013
bplusmn002
ND
NS
120572-BHC
ND
ND
ND
099
aplusmn003004
bplusmn002
ND
017
bplusmn013025
bplusmn003
ND
ND
NS
120573-BHC
ND
ND
ND
725
aplusmn001
ND
029
bplusmn013162
bplusmn077018plusmn005
bND
ND
NS
120574-BHC
ND
ND
ND
528
aplusmn001004
bplusmn001039
bplusmn017079
bplusmn006015
bplusmn001064
bplusmn053
ND
NS
Heptachlor
ND
ND
ND
116
aplusmn001
ND
ND
058
baplusmn004
001
bplusmn001109
aplusmn006
ND
NS
Aldrin
ND
ND
ND
276
aplusmn002
ND
ND
ND
ND
ND
ND
NS
Trans-chlordane174
bplusmn002
ND
001
bplusmn001458
aplusmn003
ND
ND
049
bplusmn027023
bplusmn012
ND
058
bplusmn001
NS
Cis-chlordane
ND
ND
002
bplusmn001
ND
036
bplusmn017002
bplusmn001
ND
003
bplusmn002299
aplusmn061
ND
NS
120572-end
osulfan
ND
ND
002
bplusmn001
ND
036
bplusmn007002
bplusmn001
ND
003plusmn002
b212
aplusmn019
ND
NS
120573-end
osulfan014
bplusmn007
ND
006
bplusmn002150
aplusmn001002
cplusmn001
ND
088
bplusmn002004
cplusmn002
ND
ND
NS
pp1015840-D
DE
ND
ND
006
bplusmn001791
aplusmn004151
bplusmn002037
bplusmn008501
aplusmn151013
bplusmn015035
bplusmn031
ND
NS
op1015840-D
DD
002
bplusmn001
ND
ND
518
aplusmn003
ND
ND
009
bplusmn002
001
bplusmn001
ND
ND
NS
pp1015840-D
DD
131
bplusmn008
ND
001
bplusmn0011028aplusmn001
ND
ND
148
bplusmn017013
bplusmn011
ND
ND
NS
pp1015840-D
DT
174
aplusmn001011
bplusmn000
001
bplusmn001115
bplusmn015
ND
002
bplusmn002018
bplusmn006043
bplusmn001
ND
ND
NS
Dieldrin
456
bplusmn002057
cplusmn006303
cbplusmn003882
aplusmn004099
cbplusmn053012
cplusmn006046
cplusmn003061
cplusmn011343
cbplusmn001007
cplusmn003
NS
Endrin
ND
ND
001
bplusmn001443
aplusmn004
ND
ND
032
bplusmn001012
bplusmn001
ND
ND
NS
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
4 ISRN Soil Science
Table4Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthed
ryseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
189
bplusmn005
ND
051
bplusmn0062518aplusmn305605
bplusmn002033
bplusmn012469
bplusmn153
NS
NS
ND
004
bplusmn003
120572-BHC
503
baplusmn002
ND
095
cplusmn008
001
cplusmn001232
bcplusmn153018
cplusmn003807
aplusmn300
NS
NS
ND
005
cplusmn001
120573-BHC
460
bplusmn022051
bplusmn077326
bplusmn005
001
bplusmn001010
bplusmn006131
bplusmn0061091aplusmn666
NS
NS
ND
014
bplusmn011
120574-BHC
405
bplusmn001
ND
022
bplusmn004
001
bplusmn001908
aplusmn002093
bplusmn008389
bplusmn004
NS
NS
ND
005
bplusmn001
Heptachlor
ND
bND
ND
ND
ND
ND
ND
NS
NS
ND
ND
Aldrin
655
aplusmn002
ND
003
bplusmn001
001
aplusmn001005
bplusmn003080
bplusmn037139
bplusmn005
NS
NS
ND
010
bplusmn007
Trans-chlordane264
bplusmn001
ND
380
bplusmn0038132aplusmn706026
bplusmn006047
bplusmn011288
bplusmn153
NS
NS058
bplusmn008039
bplusmn006
Cis-chlordane344
bplusmn002199
cbplusmn005020
cplusmn007106
cbplusmn003699
aplusmn005228
cbplusmn103023
cplusmn015
NS
NS103
cbplusmn100003
cplusmn001
120572-end
osulfan344
bplusmn002199
cbplusmn001020
cplusmn008106
cbplusmn003699
aplusmn002228
cbplusmn153023
cplusmn015
NS
NS103
cbplusmn071003
cplusmn001
120573-end
osulfan136
bplusmn001
ND
584
aplusmn100704
aplusmn002198
bplusmn001080
bplusmn069009
bplusmn007
NS
NS
001
bplusmn001008
bplusmn002
pp1015840-D
DE
1789aplusmn003775
bplusmn066326
bplusmn005279
bplusmn004121
bplusmn115337
bplusmn3081904aplusmn125
NS
NS008
bplusmn003019
bplusmn015
op1015840-D
DD
312
bplusmn109
ND
ND
1115aplusmn136009
bplusmn003025
bplusmn009954
aplusmn410
NS
NS
001
bplusmn001009
bplusmn007
pp1015840-D
DD
205
bplusmn001
ND
705
bplusmn0135740aplusmn676006
bplusmn005154
bplusmn136074
bplusmn016
NS
NS
001
bplusmn001008
bplusmn007
Dieldrin
238
cbplusmn001239
cbplusmn001762
aplusmn572
001
dplusmn001013
dplusmn005313
bplusmn153018
dplusmn003
NS
NS065
cdplusmn053005
dplusmn003
Endrin
114
bplusmn005
ND
022
cplusmn0162128aplusmn317011
cplusmn003039
cplusmn012054
cplusmn015
NS
NS
ND
002
cplusmn001
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
ISRN Soil Science 5
Table5Meanconcentration(120583gL)
andseason
alvaria
tionof
organo
chlorin
ecom
poun
dsin
somer
iversinOnd
oState
Analytes
Agoo-Ile
-Oluji
Ose
Ala
OLu
wa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oDry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
HCB
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120574-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Heptachlor
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Aldrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
Trans-chlordane
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
034
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
Cis-chlordane
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn009
ND
ND
ND
ND
ND
001
cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-end
osulfan
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn002
ND
ND
ND
ND
ND001cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-end
osulfan
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DE
ND
ND
ND
ND
ND
ND
011
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
opl-D
DD
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DT
ND
ND
ND
ND
ND
ND
002
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Dieldrin
ND
ND
ND
ND
107
bplusmn006
ND
151
aplusmn005
ND
ND
ND
ND
ND
ND
ND
ND025abplusmn004
ND
ND
ND
ND
ND
ND
Endrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Datainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNDnot
detected
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
4 ISRN Soil Science
Table4Meanconcentration(120583gg)
ofOCP
sinsedimentsam
ples
ofsomer
iversinOnd
oStated
uringthed
ryseason
Analytes
Agoo
Ose
Ala
Oluwa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oHCB
189
bplusmn005
ND
051
bplusmn0062518aplusmn305605
bplusmn002033
bplusmn012469
bplusmn153
NS
NS
ND
004
bplusmn003
120572-BHC
503
baplusmn002
ND
095
cplusmn008
001
cplusmn001232
bcplusmn153018
cplusmn003807
aplusmn300
NS
NS
ND
005
cplusmn001
120573-BHC
460
bplusmn022051
bplusmn077326
bplusmn005
001
bplusmn001010
bplusmn006131
bplusmn0061091aplusmn666
NS
NS
ND
014
bplusmn011
120574-BHC
405
bplusmn001
ND
022
bplusmn004
001
bplusmn001908
aplusmn002093
bplusmn008389
bplusmn004
NS
NS
ND
005
bplusmn001
Heptachlor
ND
bND
ND
ND
ND
ND
ND
NS
NS
ND
ND
Aldrin
655
aplusmn002
ND
003
bplusmn001
001
aplusmn001005
bplusmn003080
bplusmn037139
bplusmn005
NS
NS
ND
010
bplusmn007
Trans-chlordane264
bplusmn001
ND
380
bplusmn0038132aplusmn706026
bplusmn006047
bplusmn011288
bplusmn153
NS
NS058
bplusmn008039
bplusmn006
Cis-chlordane344
bplusmn002199
cbplusmn005020
cplusmn007106
cbplusmn003699
aplusmn005228
cbplusmn103023
cplusmn015
NS
NS103
cbplusmn100003
cplusmn001
120572-end
osulfan344
bplusmn002199
cbplusmn001020
cplusmn008106
cbplusmn003699
aplusmn002228
cbplusmn153023
cplusmn015
NS
NS103
cbplusmn071003
cplusmn001
120573-end
osulfan136
bplusmn001
ND
584
aplusmn100704
aplusmn002198
bplusmn001080
bplusmn069009
bplusmn007
NS
NS
001
bplusmn001008
bplusmn002
pp1015840-D
DE
1789aplusmn003775
bplusmn066326
bplusmn005279
bplusmn004121
bplusmn115337
bplusmn3081904aplusmn125
NS
NS008
bplusmn003019
bplusmn015
op1015840-D
DD
312
bplusmn109
ND
ND
1115aplusmn136009
bplusmn003025
bplusmn009954
aplusmn410
NS
NS
001
bplusmn001009
bplusmn007
pp1015840-D
DD
205
bplusmn001
ND
705
bplusmn0135740aplusmn676006
bplusmn005154
bplusmn136074
bplusmn016
NS
NS
001
bplusmn001008
bplusmn007
Dieldrin
238
cbplusmn001239
cbplusmn001762
aplusmn572
001
dplusmn001013
dplusmn005313
bplusmn153018
dplusmn003
NS
NS065
cdplusmn053005
dplusmn003
Endrin
114
bplusmn005
ND
022
cplusmn0162128aplusmn317011
cplusmn003039
cplusmn012054
cplusmn015
NS
NS
ND
002
cplusmn001
lowastDatainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNSno
sampleNDnot
detected
ISRN Soil Science 5
Table5Meanconcentration(120583gL)
andseason
alvaria
tionof
organo
chlorin
ecom
poun
dsin
somer
iversinOnd
oState
Analytes
Agoo-Ile
-Oluji
Ose
Ala
OLu
wa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oDry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
HCB
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120574-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Heptachlor
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Aldrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
Trans-chlordane
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
034
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
Cis-chlordane
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn009
ND
ND
ND
ND
ND
001
cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-end
osulfan
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn002
ND
ND
ND
ND
ND001cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-end
osulfan
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DE
ND
ND
ND
ND
ND
ND
011
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
opl-D
DD
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DT
ND
ND
ND
ND
ND
ND
002
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Dieldrin
ND
ND
ND
ND
107
bplusmn006
ND
151
aplusmn005
ND
ND
ND
ND
ND
ND
ND
ND025abplusmn004
ND
ND
ND
ND
ND
ND
Endrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Datainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNDnot
detected
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
ISRN Soil Science 5
Table5Meanconcentration(120583gL)
andseason
alvaria
tionof
organo
chlorin
ecom
poun
dsin
somer
iversinOnd
oState
Analytes
Agoo-Ile
-Oluji
Ose
Ala
OLu
wa
Ogbese
Oni
Apon
mu
Osun
Opa
Owena-Osun
Owena-Ond
oDry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
Dry
Wet
HCB
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
120574-BHC
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Heptachlor
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Aldrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
Trans-chlordane
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
034
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
Cis-chlordane
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn009
ND
ND
ND
ND
ND
001
cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120572-end
osulfan
165
aplusmn001
ND
ND
ND
ND
ND
013
bplusmn002
ND
ND
ND
ND
ND001cplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
120573-end
osulfan
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DE
ND
ND
ND
ND
ND
ND
011
aplusmn003
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
opl-D
DD
ND
ND
ND
ND
ND
ND
001
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ppl-D
DT
ND
ND
ND
ND
ND
ND
002
aplusmn001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Dieldrin
ND
ND
ND
ND
107
bplusmn006
ND
151
aplusmn005
ND
ND
ND
ND
ND
ND
ND
ND025abplusmn004
ND
ND
ND
ND
ND
ND
Endrin
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Datainthes
amec
olum
nfollo
wed
bythes
amea
lphabetsaren
otsig
nificantly
different
at120572=005usingthen
ewDun
canMultip
leRa
ngeT
estNDnot
detected
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
6 ISRN Soil Science
Table6Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthew
etseason
OCP
sPC
BsHCB120572-BHC120573-BHC120574-BHC
HEP
TAC
HLO
RALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
096
098
099
068
099
092
minus006
minus004
086
083
099
098
001
081
099
120572-BHC
100
097
097
069
096
090
minus009
minus007
090
088
096
096
minus000
076
097
120573-BHC
100
099
072
098
092
minus009
minus007
094
092
098
099
000
078
099
120574-BHC
100
078
098
091
002
004
091
089
098
098
minus000
081
099
HEP
TACH
LOR
100
067
063
053
059
074
075
068
070
minus004
070
069
ALD
RIN
100
092
minus007
minus006
086
083
099
098
002
081
099
TRANS-CH
LORD
ANE
100
minus011
minus009
086
080
093
096
037
089
093
CIS-CH
LORD
ANE
100
092
minus011minus006
minus007
minus009minus008
017
minus008
120572-ENDOSU
LFAN
100minus009
minus003
minus006
minus007minus006
021
minus006
120573-ENDOSU
LFAN
100
098
086
092
007
071
089
PP1015840 -DDE
100
084
088
minus002
066
086
OP1015840 -DDD
100
098
002
081
099
PP1015840 -DDD
100
014
084
099
PP1015840 -DDT
100
043
001
DIELD
RIN
100
080
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
ISRN Soil Science 7
Table7Re
sults
ofthec
orrelatio
ntests
forO
CPsinsedimentsam
ples
durin
gthed
ryseason
HCB120572-BHC120573-BHC120574-BHC
HEP
TACH
LOR
ALD
RIN
TRANS-
CHLO
RDANE
CIS-
CHLO
RDANE120572-ENDO
SULFAN120573-ENDO
SULFAN
PP-D
DE
OP-D
DD
PP-D
DD
PP-D
DT
DIELD
RIN
ENDRIN
HCB
100
013
0008
019
006
001
096
023
023
075
015
082
095
007
minus014
086
120572-BHC
100
093
064
092
063
minus005
031
031
004
090
057
minus007
063
007
016
120573-BHC
100
039
090
050
minus005
006
006
009
088
058
minus005
051
024
009
120574-BHC
100
046
039
minus008
086
086
011
045
021
minus009
037
027
minus002
HEP
TACH
LOR
100
081
minus005
021
021
013
094
048
minus005
083
030
026
ALD
RIN
100
minus004
034
034
034
076
024
minus005
098
021
041
TRANS-CH
LORD
ANE
100
003
003
076
004
075
099
003
minus009
089
CIS-CH
LORD
ANE
100
100
021
027
004
003
031
015
019
120572-ENDOSU
LFAN
100
021
027
004
003
031
015
019
120573-ENDOSU
LFAN
100
009
052
081
014
044
069
PP1015840 -DDE
100
057
003
076
025
032
OP1015840 -DDD
100
073
028
minus013
073
PP1015840 -DDD
100
003
minus002
088
PP1015840 -DDT
100
026
047
DIELD
RIN
100
minus001
ENDRIN
100
lowastBo
ld119903values
ares
ignificantat119875lt00001
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
8 ISRN Soil Science
Pitarch et al [15] Five watersheds relevant to the sustainabil-ity of the area were also monitored [15ndash17] for pesticides inSalmonid-bearing streams under the auspices of WashingtonState Departments of Ecology and Agriculture Residues oforganochlorine pesticides were investigated in the water andsurface sediments from the lower reaches of the YangtzeRiver to evaluate their pollution and potential risksThe studyreported that there was no obvious trend of declining DDTconcentrations in the sediments from the river [18]
Theneed for pesticide regulation and enforcement of suchwith respect to pest management safeguarding users andconsumersrsquo health and the protection of the environmentis a task that must be achieved In Nigeria apart from thenational guidelines and standards for industrial effluentsgaseous emission and hazardous wastes [19] the NationalAgency for Food and Drugs Administration and Control(NAFDAC) also made the Pesticide Registration Regulation1996 under Decree 15 of the Federal Republic of Nigeria 1993The law made application for the registration of pesticidescompulsory with prescribed guidelines The regulation spec-ified that ldquoNo pesticide shall be manufactured formulatedimported advertised sold or distributed in Nigeria unlessit has been registered in accordance with the provisions ofthese Regulationsrdquo [20] In spite of the laudable provisionslack of enforcement of the law by the regulatory agencystill makes the containment of the risk associated with theuse of pesticides an elusive task in Nigeria The marketingof pesticides in Nigeria is very much unorganized andlacks proper legislative control This has made it difficultto determine the various market sizes types and sharesof pesticides in use Hence there is no dependable officialstatistics on the type and amount of pesticides imported intothe country [21] However environmental pollution controlis just beginning to receive the desired attention in NigeriaAn important component of this is in the reliable informationon the levels of key pollutants in different media and settingsin the country Akinnifesi et al [22] investigated the physic-chemical characteristics of soils in the main cocoa producingarea of Ondo state and found that fungicide residues causeda significant increase in soil acidity organic matter andcopper concentrations The general occurrence persistenceand consequences in the environment of OCPs and thefact that it is inevitable that persistent organic pollutants(POPs) contaminated sites will continue to represent anenvironmental issue for contemporary and future generationsto address [23] make it important to determine their levels insome areas of likely predominance
Ondo State is a major cocoa producing area in NigeriaIn addition to supplying much-needed raw materials forsome local industries cocoa export is an important source offoreign exchange earnings for the country In Nigeria thereseems to be paucity of data on the monitoring of pesticideresidues in the country Cocoa farmers in Nigeria have along history of pesticide usage on their farms Cocoa beinga plantation crop had been subjected to large volume ofinsecticides annually since 1957 especially for the controlof the brown cacao mirid Sahlbergella singularis Haglund[20 21] Hence this study is designed to provide informationon the levels of OCPs in the sediments and surface water
from rivers that flow through the main cocoa-producingareas of Ondo State of Nigeria where the cocoa farmers haveemployed pesticide spraying operations on their cocoa farms
2 Materials and Methods
21 Sample Collection Preservation Preparation and Storage
211 Sampling Sites Sediment and water samples of riversin some cocoa producing areas of Ondo State Nigeriawere collected as shown in Figure 1 These rivers includedOluwaOwena-OsunOwena-OndoOseOgbese Ala AgooAponmu Oni Opa and Osun Opa and Osun rivers weresampled where there was no cocoa plantation to serve ascontrols
212 Water samples Grab sampling technique was used tocollect six core surface water samples randomly which washomogenized to form a composite sample (25 L) per riverEach was replicated thrice per season to give a total of 66samples Concentrated sulphuric acid (50mL) was addedto each of the samples immediately after the collection toprevent microbial degradation of samples The samples werekept cool during transportation to the laboratory and thenstored at 4∘C in a refrigerator until analysed
213 Sediment Samples Sediment samples were collectedfrom the 0ndash3 cm depth from the same site as water sampleswrapped up in aluminium foil and then put in a polyethylenebag Samples were kept cool during transportation to thelaboratory At the laboratory they were freeze-dried prior tosample preparation and analysis Sediment samples were laterthawed and air-dried at ambient temperature The compositedried sediment samples were processed through 20mmstainless steel sieve The less than 63 120583m soil samples wereprepared using the 63120583mstainless steel sieve prior to analysis
22 Extraction of OCPs from the Sediment and Surface WaterSamples The sample cell was packed with some glass-woolafter which 3 g sediment samples fortified with pesticidesstandards in the concentration range of 1ndash50 ppm and with500120583Lmodifier (methanolacetonemixture ratio 2 3) spikedonto the sediment was introduced and glass-wool was addedto fill the cell completely The cell was pressurized to 300 barat 60∘C with SC-CO2 (density = 0872 gmL)
The pressure was maintained for 20min (static extrac-tion) and dynamic extraction was carried out for another30minThe extract was collected into a glass tube containing5mL acetone and then concentrated to about 2mL on avacuum rotary evaporator
The extraction chamber was depressurized according tothe equipment manual The reduced extract was taken forGC-ECDanalysis Triplicate analyses of the sediment samplesfrom each study site were carried out The same procedureabove was used to extract OCPs from raw sediment samples
However standard liquidliquid extraction method wasused to isolate the OCPs from both raw and spiked surfacewater samples as suggested by Fatoki and Awofolu [24] The
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
ISRN Soil Science 9
Control pointsSample pointsPlantations
RiversState boundary
7∘09984000998400998400N
6∘09984000998400998400N
7∘09984000998400998400N
6∘09984000998400998400N
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
4∘09984000998400998400E 5
∘09984000998400998400E 6
∘09984000998400998400E
377 55 15 225 30Kilometers
0
N
Figure 1 Map of the study area showing the geographical locations of sampling points
reduced extracts were taken for GC-ECD analyses Triplicateanalyses of the water samples from each study site were done
23 Gas Chromatographic Analysis of Extracts from SedimentandWater Samples Onemicrolitre each of processed sampleforGCanalysis was injected in turns into theGC-ECD systemXL PerkinElmer used in a split less mode and equippedwith a 63Ni electron capture detector column Zebron ZB35 fused silica capillary column 30 cm times 025mm times025 120583m (film thickness) for analyses The injector anddetector temperatures were maintained at 250∘C and 300∘Crespectively The oven temperature was initially maintainedat 50∘C (hold 1min) ramped to 200∘C at 40∘Cmin (hold2min) ramped to 240∘C at 4∘Cmin (hold 1min) and finallyramped to 270∘C at 4∘Cmin (hold 5min) The carrier gaswas 99999 nitrogen gasThe carrier gas flow rate was 14 psifor optimum performance The extraction efficiencies at thedifferent temperature were determined by comparison of thepeak areas sample extract with those of the pesticide standard
mixture The response factors were determined according tostandard method [25] 2
3
4
The result of the GC-ECD determination of the OC stan-dard mixture and the calculated response factors is presentedin Table 1 All the 22 compounds were well resolved andeluted within a reasonable time of less than 30 minutes underthe optimized gas chromatograph-electron capture detector(GC-ECD) conditions The identities of the OCPs in sampleextracts were confirmed by spiking and comparing theirretention times with those of standards and concentrationswere determined by computer calculation making use ofboth the response factors of the OCPs and the internalstandard The sample clean-up techniques achieved highanalyte recoveries of 9817 plusmn 003 to 13472 plusmn 002 for SFEand 8482 plusmn 332 to 10283 plusmn 317 for LLE with RSD of lessthan 6 in both cases (Table 1) 5
24 Statistical Analysis of the Data Thevarious data obtainedwere subjected to New Duncan Multiple Range and PearsonCorrelation tests
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
10 ISRN Soil Science
3 Results and Discussion
Thegeographical locations of the sampling sites are presentedin Table 2 The results of various organochlorine pesticide(OCP) residues in the sediment are as presented in Tables 3and 4 on seasonal basis Low concentrations of OCPs wereobserved for samples taken during the wet season relativeto those for the dry season This is expected because of thedilution at the former season and the fact that the transportand dispersion of pollutants in the aquatic environment iscontrolled by advection (mass movement) and mixing ordiffusion [26] In the sediment samples all the analytes exceptheptachlor which was not detected (lt002 120583gg detectionlimit) were found at appreciably higher concentration withthe following ranges (120583gg) HCB (NDmdash2518 plusmn 305) 120572-BHC (NDmdash807 plusmn 300) 120573-BHC (NDmdash1091 plusmn 666)120574-BHC (NDmdash908 plusmn 002) aldrin (NDmdash655 plusmn 002)Trans-chlordane (NDmdash8132 plusmn 706) Cis-chlordane (003 plusmn001ndash699 plusmn 005) 120572-endosulphan (003 plusmn 001ndash699 plusmn002) 120573-endosulphan (NDmdash704 plusmn 002) pp1015840-DDE (008 plusmn003ndash1904 plusmn 125) op1015840-DDD (NDmdash1115 plusmn 136) pp1015840-DDD (NDmdash5740 plusmn 676) dieldrin (001 plusmn 001ndash762 plusmn 572)and endrin (NDmdash2128 plusmn 317) in almost all the rivers inthe dry season (Table 4) than the range (120583gg) in the wetseason HCB (NDmdash555 plusmn 001) 120572-BHC (NDmdash099 plusmn 003)120573-BHC (NDmdash725 plusmn 001) 120574-BHC (NDmdash528 plusmn 001) hep-tachlor (NDmdash116 plusmn 001) aldrin (NDmdash276 plusmn 002) Trans-chlordane (NDmdash458 plusmn 003) Cis-chlordane (NDmdash299 plusmn061) 120572-endosulphan (NDmdash212 plusmn 019) 120573-endosulphan(NDmdash150 plusmn 001) p p1015840-DDE (NDmdash791 plusmn 004) op1015840-DDD (NDmdash518 plusmn 003) pp1015840-DDD (NDmdash1028 plusmn 001)dieldrin (007 plusmn 003ndash882 plusmn 004) and endrin (NDmdash443 plusmn004) (Table 3) The high concentration of pp1015840-DDT (174 plusmn001) 120583gg in sediments from Agoo River compared to theother DDTmetabolites suggests an indication of recent usageof DDT (probably with different trade name) in the studyarea more so that at the time of sampling Agoo Rivera farmer was spraying a cocoa plantation adjacent to theriver Some of the pesticides detected in the sedimentssuch as chlordane heptachlor DDT DDE and endosulfanare known to have endocrine and estrogenic disruptingproperties [27] whichmay greatly impact on the biodiversityof the aquatic ecosystem The presence of DDT (Table 3)and some of its degradation residues in the matrix can beattributed to their wide usage before their banning [28] Sincethey are persistent enough and degrade slowly and easilyaccumulate in the soil the transportation of these pesticidesboth sorbed onto solids and dissolved by the surface waterdown to the water sources is expected [29] The persistenthalf-life of DDT in aquatic environments has been suggestedto be approximately 5 years [30] 10ndash20 years (estimated fromstudies) in bivalves [31] As various DDT metabolites persistfor a long time in the environment their gradual degradationoccurs under aerobic conditions as DDE and as DDD [32]6
7Table 5 shows the results of the determination of
organochlorine pesticide (OCP) residues in water samplesfrom various rivers on seasonal basis It has been observedthat the concentrations of analytes were very low in the
water samples (Table 5) compared to their concentrations insediment samples (Tables 3 and 4) in both dry andwet seasonThese results prove that these compounds are not hydrophilicand tend to accumulate in sediment and subsequently in fattytissue of organisms [33 34] Levels of OCPs in the surfacewater samples from all the rivers in the study area were intrace concentration (lt001 120583gL detection limit) for the wetseason analyses However some elevated levels (Table 5) of034 120583gL of trans-chlordane in Aponmu River 151 011 013and 013 120583gL of Dieldrin pp1015840-DDE cis-chlordane and 120572-endosulphan respectively in Oluwa River elevated levelsof 165 and 165 120583gL of cis-chlordane and 120572-endosulfanrespectively in Agoo River gave cause for concern Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte detectedOluwa River appeared to be the most contaminated Othercompounds were not detected because these compoundsare hydrophobic and tend to accumulate in fatty tissue oforganisms and sediment 8
9The result for dry season analyses also indicated that the
concentration ofmost of the analytes is at trace concentrationexcept for trans-chloride (034 120583gL) cis-chlordane and 120572-endosulphan (001 120583gL each) which are detected inAponmuriver and those detected in Oluwa River cis-chlordane and120572-endosulphan (013 120583gL) pp1015840-DDE (011 120583gL) op1015840-DDD(001120583gL) pp1015840-DDT (002 120583gL) and dieldrin (151 120583gL)The concentration of cis-chlordane and 120572-endosulphan inAgoo River at Ile-Oluji was 165 120583gL The amount of aldrinin Owena river at Owena-Ondo was 001120583gL 10
It was not surprising to detect DDT in water samples ofOluwa River in Ondo State DDE which is the most oftenrecognized metabolite of the DDT is a very less degradablecompound Another major reason of the presence of DDDin the river despite the fact that its production is completelybanned in the world is due to the fact that DDD wasproduced and sold by another name ldquoRothanerdquo for severalyears [28] The results showed that the concentrations ofmost of the organochlorine compounds analyzed were belowthe maximum acceptable concentration of 01120583gL value setby the European Union (EU) for the protection of aquaticenvironment 11
31 Statistical Analysis There is no significant difference inthe mean concentrations of most of the analytes detected inwater and sediment in the results of Duncan multiple rangetests (Tables 3 4 and 5)The correlation tests (Table 6) carriedout for sediment for wet season analysis revealed that most ofthe organochlorine compounds correlate positively (071 le119903 le 100)with each other at probability level of 00001while op1015840-DDD pp1015840-DDD were negatively correlated at probabilityrange of 003 to 089 However dieldrin had very low butpositive correlation within the probability range of 00158to 02371 There were strong correlations (Table 7) betweenhexachlorobenzene (HCB) and trans-chlordane (119903 = 096)120573-endosulphan (119903 = 075) op-DDD (119903 = 082) pp-DDD(119903 = 095) endrin (119903 = 086) 12
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
ISRN Soil Science 11
4 Conclusions
Supercritical fluid extraction (SFE) and liquidliquid extrac-tion (LLE) have been successfully employed for sampleclean-up of sediment and water samples respectively in thedetermination ofOCPs in thematricesThe concentrations ofcontaminants in water samples were very low as compared toconcentrations in sediment samples These results prove thatthese compounds are hydrophobic and tend to accumulatein sediments and also in fatty tissue of organisms [29] Onthe basis of the percentage of the analyte present in eachriver and the various concentration of each analyte Oluwariver is the most contaminated The high concentration ofthese contaminants is of great concern especially when theincreasing accumulation potential of these compounds in thefood chain is considered13
Due to lack of a similar survey for same study area resultscould not be compared to determine past situation of thecontamination and to estimate time trend Moreover due toabsence of such kind of previous study numerical decreasefactors could not be determined for the region Howeverthe present study can serve as reference data in the futureif routine monitoring of our environment is embarked uponby all concerned14
Acknowledgments
The fellowship granted to A A Okoya by the Southern andEastern Africa Network of Analytical Chemists (SEANAC)body which was utilized at the Department of Chem-istry University of Botswana Gaborone Botswana is highlyacknowledgedThe authors are also grateful to the authoritiesof theObafemiAwolowoUniversity for releasing her to utilizethe grant This study however forms part of the PhD thesisof A A Okoya The comments and useful suggestions ofthe reviewers have considerably improved the quality of thepaper15
References
[1] B Colin Environmental Chemistry WH Freeman and Com-pany 1999
[2] G Anitescu and L L Tavlarides ldquoSupercritical extraction ofcontaminants from soils and sedimentsrdquo Journal of SupercriticalFluids vol 38 no 2 pp 167ndash180 2006
[3] A Eqani R N Malik A Alamdar and H Faheem ldquoStatusof organochlorine contaminants in the different environmentalcompartments of Pakistan a review on occurrence and levelsrdquoBulletin of Environmental Contamination and Toxicology vol88 no 3 pp 303ndash310 2012
[4] L J Bao K A Maruya S A Snyder and E Y Zeng ldquoChinarsquoswater pollution by persistent organic pollutantsrdquoEnvironmentalPollution vol 163 pp 100ndash108 2012
[5] B Hileman ldquoEnvironmental estrogens linked to reproductiveabnormalities cancerrdquo Chemical and Engineering News vol 72no 5 pp 19ndash23 1994
[6] D L Davis and H L Bradlow ldquoCan environmental estrogenscause breast cancerrdquo Scientific American vol 273 no 4 pp166ndash172 1995
[7] WRKelce C R Stone S C Laws L EGray J A Kemppainenand E M Wilson ldquoPersistent DDT metabolite pprsquo-DDE is apotent androgen receptor antagonistrdquoNature vol 375 no 6532pp 581ndash585 1995
[8] P Cocco A Blair P Congia et al ldquoProportional mortality ofdichloro-diphenyl-trichloroethane (DDT) workers a prelimi-nary reportrdquo Archives of Environmental Health vol 52 no 4pp 299ndash303 1997
[9] D Pimentel D Andow R Dyson-Hudson et al ldquoEnvironmen-tal and social costs of pesticides a preliminary assessmentrdquoOikos vol 34 no 2 pp 126ndash140 1980
[10] UNEPTheAral Sea Diagnostic Study for the Development of anAction Plan for the Conservation of the Aral Sea Nairobi Kenya1993
[11] S A M A S Eqani R N Malik and A Mohammad ldquoThelevel and distribution of selected organochlorine pesticidesin sediments from River Chenab Pakistanrdquo EnvironmentalGeochemistry and Health vol 33 no 1 pp 33ndash47 2011
[12] M Wessel ldquoReview of the use of fertilizer on cacao in WesternNigeriardquo Annual Report 79 CRIN Ibadan Nigeria 1966
[13] L K Opeke Tropical Tree Crops JohnWiley amp Sons 1st edition1982
[14] N E Egbe E A Ayodele and C R Obatolu Soil and Nutritionof Cocoa Coffee Kola Cashew and Tea Progress in TreeResearch CRIN Ibadan Nigeria 2nd edition 1989
[15] E Pitarch CMedina T Portoles F J Lopez and F HernandezldquoDetermination of priority organic micro-pollutants in waterby gas chromatography coupled to triple quadrupole massspectrometryrdquo Analytica Chimica Acta vol 583 no 2 pp 246ndash258 2007
[16] A Johnson and J Cowles ldquoQuality assurance project planWashington state surface water monitoring program for pes-ticides in salmonid habitat a study for the Washington staterdquoDepartment of Agriculture Conducted by the WashingtonState Department of Ecology Publication Number 03-03-104httpwwwecywagovbiblio0303104html 2003
[17] C Burke and P Anderson ldquoAddendum to the quality assuranceproject plan for the surface water monitoring program forpesticides in salmonid-bearing streams addition of the skagit-samish watersheds and extension of program through June2009rdquo Washington State Department of Ecology OlympiaWash httpwwwecywagovbiblio0303104addhtml 2006
[18] Z Tang QHuang Y Yang X Zhu andH Fu ldquoOrganochlorinepesticides in the lower reaches of Yangtze River occurrenceecological risk and temporal trendsrdquoEcotoxicology and Environ-mental Safety vol 87 pp 89ndash97 2013
[19] Federal Environmental Protection Agency (FEPA) Guidelinesand Standards for Environmental Pollution Control in Nigeria1991
[20] Federal Republic of Nigeria Official Gazette Federal Govern-ment Press Lagos Nigeria 83 303ndash307 1996
[21] P N Ikemefuna ldquoPesticide importation and consumptionin Nigeriardquo in Proceedings of the Pesticide Training Work-shop on Environmentally Safe and Effective Control of PestsUNIFECSFEPA Lagos Nigeria 1998
[22] T A Akinnifesi O I Asubiojo and A A Amusan ldquoEffects offungicide residues on the physico-chemical characteristics ofsoils of a major cocoa-producing area of Nigeriardquo Science of theTotal Environment vol 366 no 2-3 pp 876ndash879 2006
[23] R Weber C Gaus M Tysklind et al ldquoDioxin- and POP-contaminated sitesmdashcontemporary and future relevance and
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
12 ISRN Soil Science
challenges overview on background aims and scope of theseriesrdquoEnvironmental Science andPollutionResearch vol 15 no5 pp 363ndash393 2008
[24] O S Fatoki and O R Awofolu ldquoLevels of organochlorinepesticide residues in marine- surface- ground- and drinkingwaters from the eastern cape province of South Africardquo Journalof Environmental Science and Health B vol 39 no 1 pp 101ndash1142004
[25] R O Awofolu and O S Fatoki ldquoPersistent organochlorinepesticide residues in freshwater systems and sediments from theEastern Cape South Africardquo Water SA vol 29 no 3 pp 323ndash330 2003
[26] C N Hewitt and R M Harrison ldquoChapter 1rdquo inUnderstandingour Environment R E Hester Ed Royal Society of ChemistryLondon UK 1st edition 1986
[27] A M Soto K L Chung and C Sonnenschein ldquoThe pesticidesendosulfan toxaphene and dieldrin have estrogenic effects onhuman estrogen-sensitive cellsrdquo Environmental Health Perspec-tives vol 102 no 4 pp 380ndash383 1994
[28] L P Van Dyk I H Wiese and J E Mullen ldquoManagement anddetermination of pesticide residues in South Africardquo ResidueReviews vol 82 pp 37ndash124 1982
[29] A Aydin and T Yurdun ldquoResidues of organochlorine pesticidesin water sources of istanbulrdquoWater Air and Soil Pollution vol111 no 1ndash4 pp 385ndash398 1999
[30] J P Villeneuve P P Carvalho SW Fowler andCCattini ldquoLev-els and trends of PCBs chlorinated pesticides and petroleumhydrocarbons in mussels from the NW Mediterranean coastcomparison of concentrations in 19731974 and 19881989rdquoScience of the Total Environment vol 237-238 pp 57ndash65 1999
[31] J L Sericano T L Wade E L Atlas and J M Brooks ldquoHis-torical perspective on the environmental bioavailability of DDTand its derivatives to Gulf of Mexico oystersrdquo EnvironmentalScience and Technology vol 24 no 10 pp 1541ndash1548 1990
[32] DW Klumpp H Huasheng C HumphreyW Xinhong and SCodi ldquoToxic contaminants and their biological effects in coastalwaters of Xiamen China I Organic pollutants in mussel andfish tissuesrdquo Marine Pollution Bulletin vol 44 no 8 pp 752ndash760 2002
[33] Washinton State Pest Monitoring Programme Pesticides andPCBs in Marine Mussels 1995 Washington State Department ofEcology 1996
[34] S Y A Chau and B K Afghan Analysis of Pesticides in WaterOntario Canada 1982
Composition Comments
1 Please provide valid postal codes to the addresses if
possible
2 We redrew some parts in Figure 1 Please check
3 We canrsquot clarify labels in Figure 1 Please check
4 We reduced font size of some labels in Figure 1 Please
check
5 There is a difference in the figure caption between the
old version and we followed the updated version and we
followed the updated one Please checko
6 Please check the correctness of the highlighted parts
Please check similar cases throughout the paper
7 We made the highlighted change for the sake of
correctness and consistency Please check
8 Please check format of Table 5
9 We made the highlighted change in Table 5 for the sake
of consistency and correctness Please check
10 We made the highlighted change in Tables 3 4 5 and
6 for the sake of consistency Please check
11 Should we change the highlighted ldquopp1-DDErdquo to
ldquopp1015840-DDErdquo in Table 5 Please check similar cases
throughout thetable
12 Please check the enumeration of the sections through-
out the paper
13 Should we change the highlighted ldquoPP-DDErdquo to
ldquopp-DDErdquo in the Table 6 Please check similar cases
throughout Tables 6 and 7
14 We changed the information of reference [18] Please
check
15 We made the highlighted changes in Acknowledg-
ments as per journal style Please check
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4
Author(s) Name(s)
Author 1
Author 2
Author 3
Author 4