ENVIRONMENTAL LONG-TERM PCB EXPOSURE OF CHILDREN IN SLOVAKIA
Eva Sovcikova, T.Trnovec, A.Kocan, J.Petrik, B.Drobna, L.Wsolova
of the 5th FP ProjectEvaluating Human Health Risk from Low-dose and Long-term PCB
Exposure (PCBRISK)
THE FUTURE FOR OUR CHILDREN Central and Eastern European Chapter Meeting of the International Society of Environmental Epidemiology
4-6 September, Balatonföldvár 2003
Children from exposed area (Michalovce district) and background area (Svidnik & Stropkov district) were examined
Inclusion criteria were
1. Children born and living in the same area, till now. Children were recruited
through their schools.
Their parents (especially mothers) permanently live in the respective
area for at least 5 years before the child’s birth.
2. Examiner (IPCM) and pediatrician (from local IPH) informed teachers and parents
about the schedule of investigation on common meetings.
Participated parents confirmed their agreement in the application form for including
of their child in the study.
- Blood sampling Venous blood (17.2ml) was withdrawn from each fasting subject (determination of PCBs, by Gas-chromatographia, thyroid hormones and heavy metals).
- The thyroid status: The subjects' thyroid status was examined by portable ultrasonography. - The anthropometric measure of children (weight, height of body, and measure of thickness of the skin layer on the arms and under the shoulder) was realized by basic equipments. - The hearing status was examined by the acoustic reflex decay test, tympanometric examination, audiometric screening, brainstem evoked potentials and oto-acoustic emissions. - Dental examination included oral hygiene, gingival health, developmental defects of enamel and caries, using the appropriate indices: Plaque Index, Loe-Silness Gingival Index, FDI Index, clinical DMFS index. Dental Questionnaire completed parents of all children.
Steps of investigation
Michalovce
KošiceBratislava
Svidnik&Stropkov
HungaryAustria
Czech Republic Poland
The
Ukr
aine
MAP OF SLOVAK REPUBLIC
Legend:
MICHALOVCE district - polluted area
SVIDNIK&STROPKOV district - non-polluted area
The neurobehavioral examination
Computer version of tests
* Simple Reaction Time: self-colored 77 stimuli were applied on display, (cca 5 min training, evaluation: measure of reactions (ms). * Viena Color Determination test: 2 minutes were applied rectangles (1x2 cm) in 6 colors (red, green, blue, yellow, black, white), training, evaluation of correct responses.
* Tapping (1 min knocking by preferred hand finger on the computer mouse and 1 min by non preferred hand finger), training, evaluation of taps number by each hand.
* Benton Recognition test (10 geometrical pictures were applied on display individually and after 10 sec, similar 4 pictures were applied), without training. Evaluation of correct pictures, number recognition.
Non-computer version of tests
* Digit Span (WISC - short hearing memory): repeating of randomly read numbers (from 2- 9, forward and backward). Evaluation: the last correct repeated number.
* Symbols (WISC – attention, motor and memory processes): completing of correct symbols of randomly ordered numbers after instruction. Evaluation: the number of correct completed symbols, time 90 sec.
* Cubes (WISC – hand coordination, attention, memory and solution proccess). Evaluation: speed of correct performance after instruction, each of 10 pictures is evaluated from 45-150 sec.
* Raven Color Nonverbal Intelligence test (solution of mental tasks): The solution of 36 pictures in sequence (max time 45 min). Evaluation: number of correct performances. Questionnaire for the filling by parents at home and Scale of child behavior at home. Raven Intelligence test (adult form) for mothers. The solution of 60 pictures (max time 45 min). Evaluation: number of correct performances. Teachers filled the Scale of Behavior at school for each child.
Total Boys Girls
MichalovceDistrict
Stropkov&SvidnikDistricts
MichalovceDistrict
Stropkov& Svidnik Districts
MichalovceDistrict
Stropkov& SvidnikDistricts
Number ofvolunteers
325 244 119 125 116 119
PCBs 218 242 108 123 110 119Lipid contentdetermination
218 242 108 123 110 119
T4, T3, anti-TPO,anti-TSH
218 242 108 123 110 119
Heavy metals inblood
218 242 108 123 110 119
Heavy metals inSerum
218 242 108 123 110 119
USG ThyroidGland examination
218 242 108 123 110 119
Samples in Total(blood, serum)
220 242 109 124 111 119
Psychologicalexamination
235 242 119 124 116 118
Dentalexamination
210 224 103 107 116 108
Table 1 Collected samples and other examinations from exposed area (Michalovce district) and from non-exposed area (Svidnik & Stropkov district).
RESULTS OF NEUROBEHAVIORAL EXAMINATION
- Levels of PCBs (with, with ½, and without LOD [ng/g lipi]) were not normal distributed (Fig 1). In continuation of analysis we used only levels of PCBs without LOD [ng/g lipi]. Collected samples and other examinations are in Tab 1.
- Descriptive analysis of PCBs in blood of children from both exposed and non- exposed area, distribution by genders are in Tab 2. Minimum of PCBs: 17.6 [ng/g lipi], Maximum of PCBs: 6476.4 [ng/g lipi].
- Children were distributed by Median of sum PCBs: Significantly higher number of children was with sum of PCBs < Me of all children in non-exposed area. Higher number of children with sum of PCBs > Me of all children was in exposed area (Fig 2). Significant difference was in sum between genders. Significantly higher levels of PCBs were in boys.
- Significant relations of PCBs levels in children and time of breast feeding (in weeks) were found (Fig 3).
- Significant relations between time of mothers´ living in the same area before child was born (in years) (Fig 4A) and significant relations between years when mother worked in chemical production and PCBs level in children were found (Fig 4B).
- - Evaluation of PCB congeners (153, 138+163, 180) between genders are in Tab 3.- Spearman Rank Correlation coefficients of measured PCB congeners, performance in behavioral tests and anthropometric parameters showed: Significantly lower performance in sensomotor (SRT, VDT) and in memory tests (DS, BNT) in children with higher level of measured PCB congeners were found. Levels of PCB congeners distributed by quartiles showed significant tendency of higher levels of congeners and lower performance in tests. The equivalent relations of PCB congeners and performance were in boys and girls, in boys these differences were stronger. Anthropometric parameters and PCB congeners showed negative significant relations too (Tab 4, Fig 5, 6, 7, 8).
Sum of PCBs without LODs [ng/g l
6500,0
6000,0
5500,0
5000,0
4500,0
4000,0
3500,0
3000,0
2500,0
2000,0
1500,0
1000,0
500,00,0
Sum of PCBs without LODs [ng/g l
Fre
qu
en
cy
200
100
0
Std. Dev = 654,78
Mean = 528,2
N = 433,00
Fig 1 Frequencies of sum PCBs in all children.
0
20
40
60
80
100
120
140
160
180
non-exposed group exposed group
num
ber o
f chi
ldre
n
Children with sum of PCB< Me (320.9))
Children with sum of PCB> Me (320.9)
Fig 2 Distribution of children by Median of sum PCBs.
Sum of PCBs withot LOD [ng/glipi] Exposed area
Sum of PCBs withot LOD [ng/glipi], non Exposed area
BOYS Sum of PCBs withot LOD [ng/glipi] Exposed area
GIRLS Sum of PCBs withot LOD [ng/glipi] Non exposed area
Mean 742.163 315.283 587.236 470.128
Median 487.284 268.212 344.303 280.824
Std. Deviation 814.100 326.295 684.666 620.351
Minimum 40.6 17.6 17.9 17.6
Maximum 6476.4 1826.4 4677.1 6476.4
Table 2 Descriptive analysis of PCBs in blood in all children and distributed by gender.
0
100
200
300
400
500
600
700
800
I. II. III. IV.
38.16 =2א p <0.001
24.63 = 2א p <0.001 Expon.grup
Control grup
Sum
of P
CB
s w
ithou
t LO
Ds
[ng/
g l]
Time of breast feeding (weeks)
Fig 3 Relation of PCBs levels in children and time of breast feeding (weeks).
0
2
4
6
8
10
12
14
16
18
I. II. III. IV.
0
100
200
300
400
500
600
700
800
900
1 2
Sum of PCBs without LODs [ng/g l]
Kruskal-Wallis test
7.70= 2 א
p= 0.0525
Sum
PC
B w
itho
ut L
OD
s [n
g/g]
(m
edia
n)
Wilcoxonov test
W = 3849
p= 0.0476
1 non-work in chemical production (years)
2 work in chemical production (years)
Mot
hers
l ive
in t h
e sa
me
area
(ye
ars)
Fig 4 Relations of mothers living in the same area (years) with PCBs levels (A). Work time of mothers in chemical production with PCBs (B).
A
B
Tab 3 The PCBs congeners without LOD [ng/g lipi] in children distributed by gender.
Boys 220 PCB153 PCB 138 PCB 180Mean 191.130 120.011 168.895
Median 117.393 73.108 96.855
Std. Deviation 210.105 136.850 205.804
Minimum 17.866 13.265 13.453
Maximum 1414.730 1011.225 1427.265
Girls 211Mean 154.348 96.740 135.075
Median 97.397 59.457 80.729
Std. Deviation 179.786 111.591 203.297
Minimum 13.670 8.931 10.804
Maximum 1757.080 1000.254 2285.59
n=428 153 138 180
Simple Reaction Time r 0.2176 sig 0.000
0.2255 0.000
0.2075 0.000
Me SRT 0.2895 0.000
0.2968 0.000
0.2748 0.000
BENTON Memory Test
- 0.1734 0.000
- 0.1678 0.001
-0.1533 0.001
Digit Span (backward) -0.2208 0.000
-0.2332 0.000
-0.2269 0.000
Viena Discrimination Test (sum)
-0.1550 0.001
-0.1630 0.001
-0.1419 0.003
Thickness of fat under Shoulder - blade
-0.2830 0.000
-0.2664 0.000
-0.2979 0.000
Thickness of fat under Arm
-0.3128 0.000
-0.2908 0.000
-0.3225 0.000
Weight of body -0.2980 0.000
-0.2806 0.000
-0.2953 0.000
Height of body -0.1870 0.000
-0.1907 0.000
-0.1883 0.000
EVALUATION OF PSYCHOLOGICAL EXAMINATION AND ANTROPOMETRIC PARAMETERS IN RELATION WITH PCBs CONGENERS
Table 4 Spearman Correlation coefficients of congeners 153,138,180 and performance in neurobehavioral tests and antrophometric parameters in all children.
Fig 5 Performance in Simple Reaction Time test and PCB congeners in blood distributed by quartiles in all children.
300
350
400
450
500
550
I II III IV
Quartile of sum of PCBs
Sim
ple
Re
ac
tio
n T
ime
(m
s)
mean
median
300
350
400
450
500
550
I II III IV
Quartile of PCB153Sim
ple
Rea
ctio
n Ti
me
(ms)
mean
median
300
350
400
450
500
550
I II III IV
Quartile of PCB138+PCB163
Sim
ple
Re
act
ion
Tim
e
(ms)
mean
median
300
350
400450
500
550
600
I II III IV
Quartile of PCB 180
Sim
ple
Re
actio
n T
ime
(ms) mean
median
Fig 6 Performance in Viena Discrimination sensomotor test and PCB congeners in blood distributed by quartiles in all children.
140
145
150
155
160
165
I II III IV
Quartile of PCB153
Vie
na
Dis
crim
inat
ion
Te
st
(su
m o
f co
rre
ct)
mean
median
140
145
150
155
160
I II III IV
Quartile of sum of PCBs
Vie
na
Dis
crim
inat
ion
Te
st
(su
m o
f co
rre
ct)
mean
median
140
145
150
155
160
165
I II III IV
Quartile of PCB138+PCB163
Vie
na
Dis
crim
inat
ion
Te
st
(su
m o
f co
rre
ct)
mean
median
140
145
150
155
160
165
I II III IV
Quartile of PCB 180
Vie
na
Dis
crim
inat
ion
Te
st
(su
m o
f co
rre
ct)
mean
median
Fig 7 Performance in Digit Span memory test (backward) and PCB congeners in blood distributed by quartiles in all children.
2,5
3
3,5
4
4,5
I II III IV
Quartile of sum of PCBs
Dig
it S
pan
(W
ISC
) b
ack
war
d
(su
m) mean
median
2,5
3
3,5
4
4,5
I II III IV
Quartile of PCB153
Dig
it S
pan
(W
ISC
) b
ack
war
d
(su
m) mean
median
2,5
3
3,5
4
4,5
I II III IV
Quartile of PCB138+PCB163
Dig
it S
pan
(W
ISC
) b
ack
war
d
(su
m) mean
median
2,5
3
3,5
4
4,5
I II III IV
Quartile of PCB 180
Dig
it S
pan
(W
ISC
) b
ack
war
d
(su
m)
mean
median
Fig 8 Performance in Benton memory test and PCB congeners in blood distributed by quartiles in all children.
7
7,58
8,5
99,5
10
I II III IV
Quartile of PCB153
Be
nto
n M
em
ory
Te
st
(su
m o
f co
rre
ct)
mean
median
77,5
88,5
99,5
10
I II III IV
Quartile of sum of PCBs
Ben
ton
Mem
ory
Tes
t
(s
um
of
corr
ect)
mean
median
7
7,5
88,5
9
9,5
10
I II III IV
Quartile of PCB138+PCB163
Be
nto
n M
em
ory
Te
st
(su
m o
f co
rre
ct)
mean
median
7
7,5
8
8,5
9
9,5
10
I II III IV
Quartile of PCB 180
Ben
ton
Mem
ory
Tes
t
(s
um
of
corr
ect)
mean
median
CONCLUSIONStatistical evaluation of PCBs level showed significant differences between children from area environmentally polluted by PCBs and children from non-exposed area.Important factors influenced level of PCBs in children were:time of breast feeding, living of mothers in the same area when child was born, and time of mothers ´work in chemical production. Neurobehavioral parameters and levels of PCBs sum and congeners showed significantly longer reaction times, lower short memory performance and lower eye-hand coordination.In the exposed area the anthropometric parameters of children were lower. Quality of neurobehavioral performances and anthropometric parameters in relation with level of PCBs and other measuredparameters between children will show the new relations in multifactor analysis.
TASKS PERFORMED BY COMPUTER
SAMPLING, THYROID GLAND AND DENTAL EXAMINATION AND ANTHROPOMETRIC MEASURE
HEARING: AUDIOMERTRY, BERA test, OTOLARYNGOLOGY examination