280 Chiang Mai J. Sci. 2011; 38(2)

Chiang Mai J. Sci. 2011; 38(2) : 280-294www.science.cmu.ac.th/journal-science/josci.htmlContributed Paper

Water Quality and Trophic Status in Main Rivers ofThailandPongpan Leelahakriengkrai*[a] and Yuwadee Peerapornpisal [a,b][a] Environmental Science Program and Center for Environmental Health, Toxicology and Management ofChemical (ETM), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.[b] Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.*Author for correspondence; e-mail: bank_2525@hotmail.com

Received: 5 July 2010Accepted: 4 December 2010

ABSTRACTThe water quality and trophic status monitoring in the main rivers of Thailand during

all three seasons in March 2008, August 2008 and January 2009 were investigated. Watersamples were collected from 6 regions in Thailand which differed in geological and usefulcharacteristics. In northern Thailand, the Ping River was selected; in the central region, theTha Chin River; in the northeast region, the Chi River; in the eastern region, the ChanthaburiRiver; in the western region, the Kwai River and in the southern region, the Tapee River.Samples were taken from the upper, middle and lower parts of each river. At each site, somephysical and chemical parameters were studied and the water quality was classified based onits trophic status. It was found that the water quality at most of the sampling sites were notclearly different and could be classified as clean-moderate water quality (oligotrophic-mesotrophic status). However, the water quality at some sampling sites were different, especially,upstream of the Ping and Tapee Rivers which could be classified as clean (oligotrophic status)and downstream of the Tha Chin River showed moderate to polluted water quality(mesotrophic-eutrophic status).

Keywords: moderate water quality, mesotrophic status, rivers, Thailand.

1. INTRODUCTIONAt present, the water quality is important

world wide. Thailand is a developing countrywith an increasing population. Some industrialand agricultural activities affect the waterquality e.g. waste discharge into the waterconsisting of organic, inorganic nitrogen andphosphorus compounds which could changewater properties. Classification of waterquality and trophic status are routine inAmerica and Europe. The water quality surveyis conducted by using some organic and

inorganic compounds such as criteria ofLorraine and Vollenweider [1] which uses totalphosphorus, total nitrogen, secchi depth andchlorophyll a to classify the trophic satatusand separate into 4 classes: oligotrophic,mesotrophic, eutrophic and hypereutrophic.Wetzel [2] used chemical oxygen demand(COD), total phosphorus, total nitrogen andtotal dissolved solid to classify the trophicstatus and separate into 8 classes: ultraoligo-trophic oligotrophic, oligomesotrophic,

Chiang Mai J. Sci. 2011; 38(2) 281

mesotrophic, mesoeutrophic, eutrophic,hypereutrophic and dystrophic. In Asia,especially in Thailand, a few methods to classifythe trophic status had been proposed. Thefirst method was modified by Peerapornpisalet al. [3] and selected such parameters as DO,BOD, conductivity and nutrients (NO3

-, NH4+

and PO43-) and separated into 7 classes:

ultraoligotrophic oligotrophic, oligotrophic-mesotrophic, mesotrophic, mesotrophic-eutrophic, eutrophic and hypereutrophic.

In Thailand, most water quality surveyswere done by the Pollution Control Department,Ministry of Natural Resources and Environ-ment and some physical and chemicalproperties were used to assess the water quality[4]. However, most recent trophic status studieswere done in the northern region [5-7]. Thisresearch present the first report of waterquality and trophic status by using physicaland chemical properties of water in some ofthe main rivers of Thailand covering 6 regions.The Ping River in northern Thailand; theTha Chin River in central region; the Chi Riverin northeast region; the Chanthaburi River ineastern region; the Kwai River in westernregion and the Tapee River in southern region.The results of the water quality and trophicstatus in some main rivers will be shown inthe database of Thailand water quality bytrophic status.

2. MATERIALS AND METHODSThe study areas are located in 6 regions

of Thailand. In northern Thailand, Ping River(5 sites) was selected; in central region,Tha Chin River (5 sites); in northeastern region,Chi River (5 sites); in western region, KwaiRiver (5 sites); in eastern region, ChanthaburiRiver(4 sites) and in southern region, TapeeRiver (4 sites) (Table 1 and Figure 1). Thewaters were sampled from upstream todownstream during summer, rainy and cooldry seasons during March 2008 - January 2009.

Some physical and chemical propertiesof water were determined at the samplingsites. The temperature, pH, conductivity, totaldissolved solid and salinity were measuredusing the multimeter (electrode kit of WTWCompany). Measurement of some chemicalproperties of water was done by the methodof Eaton et al. [8]. Dissolved oxygen (DO)and BOD5 were measured using the azidemodification method. Alkalinity was measuredby phenolpthalein methyl orange indicatormethod. Concentrations of nutrients, i.e.ammonia-nitrogen, nitrate-nitrogen andsoluble reactive phosphorus (SRP) weredetermined in the laboratory by nesslerization,cadmium reduction and ascorbic acidmethods, respectively.

The trophic status of water was evaluatedfrom the main parameters (conductivity, DO,BOD5, ammonia-nitrogen, nitrate-nitrogenand soluble reactive phosphorus) by theApplied Algal Research Laboratory Physicaland Chemical score (AARL PC score) (Tables2, 3) according to Lorraine and Vollenweider[1], Wetzel [2], Peerapornpisal et al. [3] andPollution Control Department [9]. Thecalculation of trophic status from AARL PCscore is shown in Table 4.

The relationship of water properties andsampling sites were analyzed using PrincipalComponent Analysis (PCA) and ClusterAnalysis (CA) in Multivariate Statistical Packageversion 3.1 (MVSP).

3. RESULTS AND DISCUSSION3.1 Water Quality and Trophic Status

Some physical and chemical propertiesof water in each of the sampling sites areshown in Table 5. The water quality of thePing River at the upstream area (MP1) in termsof BOD5, TDS, conductivity, alkalinity andnutrients (ammonia-nitrogen, nitrate-nitrogenand soluble reactive phosphorus) werefound to be at low level. MP2 showed high

282 Chiang Mai J. Sci. 2011; 38(2)

ammonia-nitrogen and SRP and mostsampling sites at the downstream showed nodifference in water properties. All samplesfrom the Tha Chin River at TC1, 2 and 3showed high level of DO and low level ofBOD5, TDS, conductivity, alkalinity, SRP,ammonia-nitrogen and nitrate-nitrogencompared to those at. TC4 and 5. CH1, 2

and 3 of Chi River showed high level ofsalinity, conductivity and TDS especially atCH2 in summer season showed highest levelof salinity, conductivity and TDS. At TapeeRiver, high level of DO and low level ofTDS, conductivity and alkalinity were foundin samples from TP1. Most of the samplingsites downstream in the Tapee River showed

Name of sitesLocations Latitudes and Altitudes

District and Province Longitudes (m)

MP1 Chiang Dao, Chiang Mai 19o45″359′N 98o53″720′E 841MP2 Mueang, Chiang Mai 19o44″270′N 98o58″916′E 350MP3 Ban Tak, Tak 17o02″186′N 99o04″015′E 325MP4 Khlong Khlung, Kamphaeng Phet 16o16″012′N 99o41″449′E 58MP5 Mueang, Nakhon Sawan 15o42″697′N 100o08″685′E 42

TC1 Wat Sing, Chainat 15o12″748′N 100o04″200′E 18TC2 Sam Chuk, Suphan Buri 14o44″454′N 100o06″086′E 9TC3 Bang Pla Ma, Suphan Buri 14o24″103′N 100o09″392′E 8TC4 Samphran, Nakhon Pathom 13o44″613′N 100o15″568′E 3TC5 Krathum Baen, Samut Sakhon 13o39″985′N 100o16″074′E 1

CH1 Nong Bua Daeng, Chaiyaphum 16o03″543′N 101o40″004′E 218CH2 Chonnabot, Khon Kaen 16o05″790′N 102o34″302′E 163CH3 Kosum Pisai, Mahasarakham 16o15″055′N 103o04″409′E 139CH4 Mahachaichana, Yasothon 15o31″444′N 104o15″003′E 133CH5 Khueang Nai, Ubon Ratchathani 15o18″653′N 104o26″184′E 124

KW1 Srisawat, Kanchanaburi 14o23″167′N 99o08″631′E 102KW2 Srisawat, Kanchanaburi 14o18″041′N 99o12″724′E 66KW3 Mueang, Kanchanaburi 14o13″804′N 99o14″399′E 19KW4 Mueang, Kanchanaburi 14o05″992′N 99o24″858′E 18KW5 Mueang, Kanchanaburi 14o02″495′N 99o30″224′E 5

TP1 Phipoon, Nakhon Si Thammarat 08o32″454′N 99o40″973′E 206TP2 Phrasaeng, Surat Thani 08o34″261′N 99o15″271′E 77TP3 Khian Sa, Surat Thani 08o51″957′N 99o11″853′E 33TP4 Phun Phin, Surat Thani 09o06″035′N 99o13″829′E 1

CB1 Khao Khitchakut, Chantaburi 12o49″854′N 102o04″644′E 78CB2 Khao Khitchakut, Chantaburi 12o47″656′N 102o06″747′E 60CB3 Mueang Chantaburi 12o38″165′N 102o08″265′E 19CB4 Mueang, Chantaburi 12o37″493′N 102o07″380′E 18

* MP= Ping River, TC= Tha Chin River, CH= Chi River,KW=Kwai River, TP=Tapee River, CB=Chanthaburi River

Table 1. Sampling sites and their topography.

Chiang Mai J. Sci. 2011; 38(2) 283

high levels of TDS, conductivity and alkalinity.At the Kwai and Chanthaburi Rivers nodifferences in the water quality at each site werefound. The Kwai River showed low levelsof turbidity, SRP, ammonia- nitrogen and

nitrate- nitrogen. The Chanthaburi Rivershowed low levels of turbidity, TDS andconductivity and high level of DO.

The trophic status and AARL PC scoreof water at each sampling site were shown in

Figure 1. Map of Thailand showed Ping, Tha Chin, Chi, Kwai, Tapee and ChanthaburiRivers and sampling sites.

284 Chiang Mai J. Sci. 2011; 38(2)

SRP(mg.l -1)

score

<0.05 0.10.05-0.2 0.20.2-0.4 0.30.4-0.8 0.40.8-1.5 0.51.5-3.0 0.63.0-5.0 0.75.0-10.0 0.810.0-20.0 0.9

>20.0 1.0

Table 2. Applied Algal Research Laboratory Physical and Chemical score (AARL PC score)for DO, BOD5, conductivity, nitrate-nitrogen, ammonia-nitrogen and soluble reactivephosphorus.

conductivity(μμμμμS.cm-1)

score

<10 0.110-20 0.220-40 0.340-70 0.470-100 0.5100-150 0.6150-230 0.7230-400 0.8400-550 0.9

>550 1.0

D O(mg.l -1)

score

>8 0.17-8 0.26-7 0.35-6 0.44-5 0.53-4 0.62-3 0.71-2 0.8

0.5-1 0.9<0.5 1.0

BOD5

(mg.l -1)score

<0.25 0.10.25-0.5 0.2

0.5-1 0.31-2 0.42-4 0.54-10 0.610-20 0.720-40 0.840-80 0.9>80 1.0

NO3-N

(mg.l -1)score

<0.05 0.10.05-0.1 0.20.1-0.3 0.30.3-0.8 0.40.8-1.5 0.51.5-3.0 0.63.0-10.0 0.710.0-20.0 0.820.0-40.0 0.9

> 40.0 1.0

NH3-N

(mg.l -1)score

<0.1 0.10.1-0.2 0.20.2-0.4 0.30.4-0.8 0.40.8-1.5 0.51.5-3.0 0.63.0-5.0 0.75.0-10.0 0.810.0-20.0 0.9

>20.0 1.0

Table 3. Seven classes of trophic status based on AARL PC score.Score Trophic status Water quality< 0.8 ultraoligotrophic very clean

0.9-1.6 oligotrophic clean1.7-2.4 oligotrophic-mesotrophic clean-moderate2.5-3.2 mesotrophic moderate3.3-4.0 mesotrophic-eutrophic moderate-polluted4.1-4.8 eutrophic polluted> 4.8 hypereutrophic very polluted

Chiang Mai J. Sci. 2011; 38(2) 285

Table 6. Most of the sampling sites showeddifferent trophic status in each season due todifferent activities along the rivers. Ping andChi Rivers were cleaner at the upstream areabecause these areas were surrounded bydeciduous forest so there was not muchcontamination of the water bodies and thedownstream was more contaminated by thecommunity and agricultural activities. Whilst,Chanthaburi and Tapee Rivers were locatedin the western and southern regions withlonger period of rainy season and short lengthof the rivers, therefore the change in waterquality were not much in each season. The waterat most sampling sites in the Ping River wereclassified in the oligotrophic-mesotrophicstatus, except at MP1, during the rainy seasonwhich was oligotrophic and at MP2, in allseasons, was mesotrophic. The Tha Chin Riverwas classified as mesotrophic, except at TC4and 5 which were mesotrophic-eutrotrophic.Tapee River was classified as oligotrophic-mesotrophic, except at TP1, in all seasons wasoligotrophic. Most of the sampling sites inthe Chi, Kwai and Chanthaburi Rivers wereclassified in the oligotrophic-mesotrophicstatus, except those at KW2 and 3 of theKwai River were mesotrophic and CB2 ofChanthaburi River in cool dry season wasoligotrophic status.

3.2 Statistical AnalysisIn Asia and Europe, the PCA and CA

were primary methods for description ofcorrelation between sampling sites andphysico-chemical parameters [10-12]. ThePCA showed positive and negative correlation.The positive correlations were conductivity,total dissolved solid, salinity and alkalinity(axis 1; 0.433, 0.431, 0.438, 0.341, axis2; 0.141,0.170, 0.092, 0.114), air and water temperatures(axis 1; 0.032, 0.133, axis2; 0.160, 0.166),ammonia-nitrogen and soluble reactivephosphorus (axis 1; 0.241, 0.204, axis2; -0.496,-0.501). The negative correlations were DOand BOD5 (axis 1; -0.323, 0.253, axis2; 0.184,-0.157). Besides, nitrate-nitrogen (axis 1; -0.097,axis2; -0.365) showed negative correlationwith conductivity, total dissolved solid, salinityand alkalinity (Figure 2). The CA of waterproperties in the main rivers of Thailandshowed 6 groups with 75% similarity. Groups1 were all samples from MP1 at Ping Riverand all samples in Chanthaburi River. Group2 were all samples from TP1 in Tapee Riverand CH1 of Chi River in rainy season was inGroup 3. Most of the sampling sites wereincluded in Group 4 and downstream of ThaChin River were in Group 5. Only CH2 ofChi River in summer season was in Group 6(Figure 3).

Parameters Levels AARL PC score*

DO (mg.l -1) 7.8 0.2BOD5 (mg.l -1) 1.4 0.4conductivity (μS.cm--

-1) 53.2 0.4NO3-N (mg.l -1) 0.3 0.3NH3-N (mg.l -1) 0.31 0.3SRP (mg.l -1) 0.01 0.1

Total score 1.7 **Trophic status oligotrophic-mesotrophic status**

* from Table 2, ** from Table 3

Table 4. Trophic status calculated from AARL PC score of MP1 in summer.

286 Chiang Mai J. Sci. 2011; 38(2)T

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259

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0.16

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27-3

326

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6.92

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952

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08-0

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CB4

24-3

023

-32

6.04

-7.1

19.

7-26

.30-

45.3

016

.3-3

3.5

37.5

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74.

6-7.

51.

1-3.

10.

27-0

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0.2

0.02

-0.5

Chiang Mai J. Sci. 2011; 38(2) 287

Name ofsites summer rainy cool dry summer rainy cool dry

MP1 1.7 1.2 1.7 oligo-meso oligo oligo-mesoMP2 2.5 2.7 2.9 meso meso mesoMP3 2.2 2.3 2.5 oligo-meso oligo-meso mesoMP4 1.7 2.2 2.5 oligo-meso oligo-meso mesoMP5 2.3 2.6 2.4 oligo-meso meso oligo-mesoTC1 2.2 2.6 2.7 oligo-meso meso mesoTC2 2.4 3.0 3.0 oligo-meso meso mesoTC3 3.0 3.0 3.0 meso meso mesoTC4 3.3 3.2 3.6 meso-eutro meso meso-eutroTC5 3.8 3.4 3.7 meso-eutro meso-eutro meso-eutroCH1 2.5 1.9 2.1 meso oligo-meso oligo-mesoCH2 2.4 2.2 2.7 oligo-meso oligo-meso mesoCH3 2.6 2.5 2.1 meso meso oligo-mesoCH4 2.2 2.5 2.6 oligo-meso meso mesoCH5 2.4 2.4 2.7 oligo-meso oligo-meso mesoKW1 2.3 2.4 2.4 oligo-meso oligo-meso oligo-mesoKW2 2.8 2.5 2.8 meso meso mesoKW3 2.8 2.5 2.5 meso meso mesoKW4 2.5 1.9 2.3 meso oligo-meso oligo-mesoKW5 2.3 2.4 2.4 oligo-meso oligo-meso oligo-mesoTP1 1.1 1.6 1.5 oligo oligo oligoTP2 2.4 2.2 2.1 oligo-meso oligo-meso oligo-mesoTP3 2.2 2.1 2.0 oligo-meso oligo-meso oligo-mesoTP4 2.4 2.3 2.2 oligo-meso oligo-meso oligo-mesoCB1 1.7 1.7 2.1 oligo-meso oligo-meso oligo-mesoCB2 2.1 1.6 2.4 oligo-meso oligo oligo-mesoCB3 2.0 2.0 2.3 oligo-meso oligo-meso oligo-mesoCB4 2.0 1.7 2.4 oligo-meso oligo-meso oligo-meso

Table 6. Water quality by trophic status in each sampling site and season of 6 main rivers ofThailand.

AARL-PC score Trophic status

288 Chiang Mai J. Sci. 2011; 38(2)

Figure 2. The principal component analysis (PCA) indicating correlation of water propertiesin 6 main rivers of Thailand.

In this study, 80% similarity of CA in thePing, Tha Chin, Chi and Tapee Rivers wereselected on the basis of physical and chemicalfactors. The Ping River showed 3 groups; allsamples of MP1 were in Group 1 becausethis site was located at the upstream area withlow levels of BOD5, TDS, conductivity,alkalinity and nutrients (ammonia-nitrogen,nitrate-nitrogen and soluble reactive phos-phorus). The water quality was clean tomoderate and classified in the oligo-mesotrophic status based on AARL PC score,especially in the rainy season which wassimilar to that reported by Kunpradid andPeerapornpisal [13]. Most of the samplingsites were in Group 2. Only MP2 in rainyseasons was in Group 3 because it wasaffected by Mae Kha Canal i.e. waste waterfrom this canal mixed with water bodies andshowed high ammonia-nitrogen, SRP andlow level of DO. The water quality was

moderate and classified in the mesotrophicstatus (Tables 5 and 6; Figures 4 and 5).

At Tha Chin River, all samples of TC1,2 and 3 were in Group 1 which showed highlevel of DO and low levels of BOD5, TDS,conductivity, alkalinity, SRP, ammonia-nitrogenand nitrate-nitrogen. The water quality wasmoderate and classified in the mesotrophicstatus. Group 2 included TC4 and 5 whichwere downstream of Tha Chin River. Thewater was moderate to polluted quality andclassified in the meso-eutrophic status whichwas similar to the report by Simachaya [14]and Petipong [15] (Tables 5 and 6; Figures 4and 5).

There were 5 groups at Chi River. CH1and 2 of summer and cool dry seasons werewithin group 1 with high levels of salinity,conductivity and TDS. All samples of CH3,4 and 5 were in Group 2 with high levels ofSRP, ammonia-nitrogen and nitrate-nitrogen.

Chiang Mai J. Sci. 2011; 38(2) 289

Fig

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290 Chiang Mai J. Sci. 2011; 38(2)

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Chiang Mai J. Sci. 2011; 38(2) 291

Figure 5. The principal component analysis (PCA) of water properties showing correlationbetween physico-chemical parameters and sampling sites in 6 main rivers of Thailand.

Ping River Tha Chin River

Chi River Kwai River

Tapee River Chanthaburi River

292 Chiang Mai J. Sci. 2011; 38(2)

Only CH1 of cool dry season was in Group3 with high levels of BOD5 and pH. Group4 was only CH1 of rainy season with a highlevel of nitrate-nitrogen and low level ofBOD5, salinity, conductivity and TDS. Group5 was only CH2 of summer season whichshowed highest level of salinity, conductivityand TDS with values 0.5±0.00%, 992±2.65μs/cm and 558±0.00 mg/L. This was due tothe dissolution of saline soil into water body[16, 17]. The water quality of Groups 2, 3and 4 were clean to moderate and classifiedin the oligo-mesotrophic status whereasGroups 1 and 5 were moderate and classifiedin the mesotrophic status (Tables 5 and 6;Figures 4 and 5).

The Tapee River showed 3 groups.Group 1 was all samples of TP1 because itwas located in a National Park with high levelsof DO and low levels of TDS, conductivityand alkalinity which was similar to the reportby Petipong [15]. The water quality was cleanand classified in the oligotrophic status.Group 2 had all samples of TP2 and 3 insummer season with high level of TDS,conductivity and alkalinity. Group 3 had mostof the sampling sites and the water qualitywas clean to moderate and classified in theoligo-mesotrophic status which was similarto the report by Petipong [15] and Chuaygudet al. [18]. (Tables 5 and 6; Figures 4 and 5).

The 90% similarity of CA was selectedfor the Kwai and Chanthaburi Rivers. Therewere 2 groups for the Kwai River, Group 1was all samples in summer season with highlevels of TDS, conductivity, alkalinity and lowlevels of turbidity which was similar to thereport by Tyler [19]. Group 2 was all samplesin rainy and cool dry season. In addition, atChanthaburi River, there were 3 groups byseasons. Group 1 was all samples in summerseason with high level of water temperatureand low level of DO and nitrate-nitrogen.All samples in rainy season were in Group 2

with high level of turbidity and low levels ofTDS, conductivity, alkalinity. Group 3 was allsamples in cool dry season with high levelsof DO, BOD5 and nitrate- nitrogen. Thewater quality of Kwai and Chanthaburi Riverswas clean to moderate and classified in theoligo-mesotrophic status which was similarto the report by Petipong [15] and Bordaloet al. [20]. (Tables 5 and 6; Figures 4 and 5).

4. CONCLUSIONSThe water quality of some of the main

rivers of Thailand from March 2008 - January2009 showed mostly clean to moderate andclassified in the oligotrophic-mesotrophicstatus, except in the upstream of the Ping andTapee Rivers which were clean and classifiedin the oligotrophic status. Besides, thedownstream of the Tha Chin River showedmoderate to polluted water quality andclassified in the mesotrophic-eutrophic status.

In this investigation, beneficial usages ofeach river were recommended by standardsurface water quality of Thailand [21]. ThePing, Chi, Kwai, Chanthaburi and Tapee Riverscould be used for agriculture, industry andcommunication. Tha Chin River could be usedfor industry and communication. The waterhas to undergo an ordinary treatment processbefore use for consumption. However, thewater from Tha Chin River requires specialtreatment.

ACKNOWLEDGEMENTSThe authors would like to thank the

Biodiversity Research and Training Program(BRT), the Center of Excellence on Environ-mental Health, Toxicology and Managementof Chemicals (ETM) and the GraduateSchool, Chiang Mai University for providingfinancial support.

Chiang Mai J. Sci. 2011; 38(2) 293

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