- Email: [email protected]
Human biomonitoring system in the Czech Republic
ARTICLE IN PRESS
Int. J. Hyg. Environ.-Health 210 (2007) 495–499 www.elsevier.de/ijheh
Human biomonitoring system in the Czech Republic Milena Cˇerna´a,b,, Ve˘ra Spe˘va´cˇkova´a, Andrea Bata´riova´a,b, Jirˇ ı´ Sˇmı´ da, Ma´ja Cˇejchanova´a, Dana Ocˇadlı´ kova´a, Hana Bavorova´a, Bohuslav Benesˇ a, Ru˚z˘ena Kubı´ nova´a National Institute of Public Health, Centre of Environmental Health, Sˇroba´rova 48, 10042 Prague 10, Czech Republic Charles University, 3rd Faculty of Medicine in Prague, Czech Republic
a
b
Abstract The human biomonitoring (HBM) is an integral part of Environmental Health Monitoring System in the Czech Republic since 1994. Selected biomarkers of the internal dose (heavy metals, PCBs) and cytogenetic analysis of peripheral lymphocytes as a biomarker of the exposure/effect to/of environmental genotoxic factors are systematically followed up in the blood and urine of adults (blood donors), in children aged 8 to 10 years, and in the breast milk of nursing mothers. Selected outputs documented the declining trend of blood lead levels, with the recent reference value of 80 mg/l for men, and the rising trend of blood selenium levels in adults, but not in children. PCBs and chlorinated pesticides in human milk show a long-term downward trend, but still higher than in neighbouring countries. The frequency of aberrant cells revealed a downward trend, but the increase obtained in the last monitored period needs to be explained. Further HBM activities are required to demonstrate the corresponding trends and to reduce human exposure and health risks. r 2007 Elsevier GmbH. All rights reserved. Keywords: Human biomonitoring; Czech Republic; Heavy metals; PCBs; Chromosomal aberrations
Introduction The Environmental Health Monitoring System (EHMS) in the Czech Republic based on Govt. Decree No. 369/1991 has been run routinely since 1994 and includes altogether eight subsystems oriented on health risks of environment and health interactions (www.szu.cz, Kliment et al., 2000). The aim of EHMS is to provide the data that (a) are necessary for adopting a national policy of health and environmental protection, (b) provide the background for legislative measures Corresponding author. National Institute of Public Health, Centre of Environmental Health, Sˇroba´rova 48, 10042 Prague 10, Czech Republic. Tel./fax:+420 267082378. E-mail address: [email protected] (M. Cˇerna´).
1438-4639/$ - see front matter r 2007 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijheh.2007.01.005
to be taken, (c) are linked to the environmental data obtained in the integral monitoring system, (d) help establish the threshold values and control their effectiveness, (e) enable to follow-up the long-term time trends and (f) facilitate international comparison of environmental health data. From the beginning human biomonitoring (HBM) represents an integral part of EHMS with the aim to assess the exposure of the Czech general population to a broad spectrum of environmental contaminants monitored in other environmental media including the diet. The main objectives of HBM are (a) to document the extent, the distribution and the determinants of exposure to important environmental pollutants by means of proper biomarkers of exposure and/or effects, (b) to follow-up long-term time trends, (c) to establish reference values for the Czech population
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
496
the National Institute of Public Health in Prague. A standardized operational protocol is used for sampling, labelling, transport and storage of human body fluids and tissue samples with special respect to the selected biomarkers. The selection of pollutant classes that are followed up in the body fluids and tissues was based on their measurement in the diet, air and drinking water within the EHMS, on their potential influences on human health, probability of population exposure and availability of health-relevant biomarkers to measure the internal dose or biological effective dose. Cytogenetic analysis of human peripheral lymphocytes was selected as a biomarker of exposure/effect to environmental genotoxic factors for both adults and children. Biomarkers were chosen on the basis of the availability of human body fluids sampling procedures in children and adults, likewise analytical methods that are well proven and suitable to analyze a large number of samples, and the accessibility of accredited laboratories equipped with advanced technique and skilled personnel have been considered. The broad spectrum of biomarkers exposure measured in human body fluids and tissues of the Czech general population is summarized in Table 1. Analysis of selected biomarkers is carried out according to the matrix/analytes using validated methods in laboratories accredited by the Czech Institute of Accreditation. The laboratories use reference materials, control samples and blanks, and participated in international comparative studies.
and (d) to generate information for strategies of exposure prevention and restriction. In this paper, we briefly describe the scenario of HBM in the Czech Republic and selected outputs. The data obtained are published on an ongoing basis.
Materials and methods In the period 1994–2003, HBM was conducted in four urban/suburban areas; two of them (Plzenˇ, U´stı´ n.L.) with a higher level of industrialization and traffic load, the remaining two (Benesˇ ov, Zˇd’a´r n.S.) represent more rural areas. Since 2005, the monitored urban areas with a potential of increased exposure include the capital Prague and Ostrava in northern Moravia; the less polluted urban areas are Liberec, Krome˘rˇ ı´ z˘ and Uherske´ Hradisˇ te˘. Only residents for a period of not less than 2 years in selected urban areas are included in the survey. Blood and urine samples are obtained from healthy adult blood donors aged 18–58 years and children aged 8–10 years, Breast milk samples are obtained from nursing mothers (preferentially primiparae) according to the WHO protocol (WHO/ECEH, 1996). Each year, about 100 subjects from each population group and urban area are selected. Informed consent is obtained from each sampled person or from the parents of sampled children. A short questionnaire is used to obtain information on age, weight, height, and stay in the locality, medication, occupational exposure and lifestyle habits, above all smoking. The HBM survey has been approved by the ethical committee of Table 1.
Matrices and analytes followed in the Czech HBM
Population
Matrix
Analytes
Adults–blood donors aged 18–58 years
Blood
Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se. Zn) Cytogenetic analysis of the peripheral lymphocytes Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs) Ochratoxin A Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn, I) Creatinine Cotinine (since 2005)
Blood serum
Urine
Children aged 8–10 years
Blood
Hair
Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn) Cytogenetic analysis of the peripheral lymphocytes Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn, I) Creatinine Cotinine (since 2005) Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn)
Children aged 5–6 years
Deciduous teeth
Pb
Nursing mothers
Breast milk
Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs)
Autopsies
Subcutaneous fat
Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs)
Urine
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
497
of results below the LOD was greater than 50%, the descriptive statistics were not calculated. The 95th percentile levels and appropriate confidence intervals are used for reference values proposal.
Statistics The results in the form of descriptive statistics are expressed in mg/l (blood), mg/g creatinine (urine), mg/g (hair, teeth) and mg/kg fat (breast milk, subcutaneous fat). Data were processed using the statistical software packages Unistat 5.1 and Statistica version 7. For the statistical calculation, the data below the limit of detection (LOD) of the method used were replaced by a value equal to one-half of the LOD. If the proportion
Selected results Each year, the description of yearlong HBM activity results in the form of descriptive statistics, and inter-
60
50
49
Males
Females
Boys
Girls
49 44
45
44
40
40
38 36 34
34
µg / L
32 30
30
30
29
30
27
35
34
33
32 28
27
25 22
20
10
0
1996
1997
1998
1999 2000 Years
2001
2002
2003
Fig. 1. Blood-lead levels in monitored adults and children (median, mg/l). 180
160 Median
25% - 75%
5% - 95%
140
µg /l
120
116
100 91
92
2000
2001
89
80
89
79
73
70
60
40
20
1996
1997
1998
1999
2002
Years
Fig. 2. Blood selenium level in monitored adults (mg/l).
2003
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
498
in 1996/98 was assessed to be 95 mg/l (Cˇerna´ et al., 2001), and 80 mg/l in 2003/04 (Bata´riova´ et al., 2006). In children, the B-Pb median values are about 30 mg/l with no significant trend in time; only 0.8% (n ¼ 12) of monitored children had elevated B-Pb levels above 100 mg/l. Blood cadmium levels in non-smokers are about 3 times lower than in smoking adults; the levels in urine are higher in women that in men (Puklova´ et al., 2005). In children, the blood and urine concentrations
pretation data are indicated in the Technical and Summary Annual Reports and on the web sites of the National Institute of Public Health (www.szu.cz). Only selected results as output examples are presented here. Blood lead levels (B-Pb) in adults are higher in men that in women and have declined significantly during the monitoring period (Fig. 1) with only 0.9% (n ¼ 28) of values above the health relevant HBM limit of 150 mg/l (Ewers et al., 1999). The reference value for male adults
800
700 Median
25% - 75%
5% - 95%
600
µg / kg fat
500
400 352 323
300 201
200
165
165
174
168
164
139
137
100
0
1994
1995
1996
1997
1998 1999 Years
2000
2001
2002
2003
Fig. 3. Time-related levels of PCB indicator congener in breast milk.
1.8 1.65
1.6 1.4
Adults 1.4 1.29
1.26
1.23
1.2
1.14 1.06
1.04
% AB.C.
Children
1
1.1
0.92
0.8 0.6 0.4 0.2 0 1994
1995
1996
1999
2001
2003
Years
Fig. 4. Frequency of chromosomal aberrations in the monitored children and adults.
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
are mostly below the detection limit of the method used. Blood selenium levels in adults increased significantly with time being consistent with a similar upward trend of selenium in the diet (Fig. 2) (Bata´riova´ et al., 2005). Polychlorinated biphenyls (PCB) and chlorinated pesticides measured in breast milk show a long-term declining trend (Fig. 3) (Cˇerna´ et al., 2003). Reference values for PCB 153 congener in 1994/95 (700 ng/g fat) was about twice as high as for breast milk in the German Survey of 1990/92 (Ewers et al., 1999), whereas the comparable reference value for the Czech population (330 ng/g fat) was obtained in 2002/03 only. Cytogenetic analysis of human peripheral lymphocytes has been used in the Czech Republic since 1974 to assess occupational exposure to clastogenic chemicals (Ro¨ssner et al., 1998) and we suppose that this biomarker might be used as a biomarker of environmental pollution. The frequency of aberrant cells markedly decreased within the monitored period 1994–2001 in both, children (Ro¨ssner et al., 2002) and adults. However, an increase in the level of chromosomal aberrations was observed in adults in the last monitored period (2003) when children were not sampled (Fig. 4).
Conclusion Biomonitoring assessment of the exposure of the Czech population represents an important part of risk assessment and risk management process. The levels of most, but not all monitored biomarkers of exposure show a gradual decline in time reflecting the effectiveness of preventive measures on the improvement of environmental pollution and lifestyle habits. Reference values can be used to identify population subgroups or individuals with an increased level of exposure. Further monitoring is required in order to establish an adequate database to demonstrate trends, and to reduce human exposure and health risks.
499
References Bata´riova´, A., Cˇerna´, M., Spe˘va´cˇkova´, V., Cˇejchanova´, M., Benesˇ , B., Sˇmı´ d, J., 2005. Whole blood selenium content in healthy adults in the Czech Republic. Sci. Total Environ. 338, 183–188. Bata´riova´, A., Spe˘va´cˇkova´, V., Benesˇ , B., Cˇejchanova´, M., Sˇmı´ d, J., Cˇerna´, M., 2006. Blood and urine levels of Pb, Cd and Hg in the general population of the Czech Republic and proposed reference values. Int. J. Hyg. Environ. Health 209, 359–366. Cˇerna´, M., Spe˘va´cˇkova´, V., Benesˇ , B., Cˇejchanova´, M., Sˇmı´ d, J., 2001. Reference values for lead and cadmium in blood of Czech population. Int. J. Occup. Med. Environ. Health 14, 189–192. Cˇerna´, M., Sˇmı´ d, J., Svobodnı´ k, J., Grabic, R., Crhova´, Sˇ., Kubı´ nova´, R., 2003. Monitoring of selected polyhalogenated hydrocarbons in breast milk: Czech Republic, 1994 to 2001. FEB 12 (2), 203–207. Ewers, U., Kraus, C., Schulz, Ch., Wilhelm, M., 1999. Reference values and human biological monitoring values for environmental toxins. Int. Arch. Occup. Environ. Health 72, 255–260. Kliment, V., Kubı´ nova´, R., Kazmarova´, H., Kratzer, K., Sˇisˇ ma, P., Ruprich, J., Cˇerna´, M., Gregu˚rkova´, M., 2000. Five years of the system of monitoring the environmental impact on population health of the Czech Republic. Central Eur. J. Publ. Health 8, 198–205. Puklova´, V., Bata´riova´, A., Cˇerna´, M., Kotlı´ k, B., Kratzer, K., Melichercˇı´ k, J., Ruprich, J., Rˇehu˚rˇ kova´, I., Spe˘va´cˇkova´, V., 2005. Cadmium exposure pathways in the Czech urban population. Central Eur. J. Publ. Health 13 (1), 11–19. Ro¨ssner, P., Sˇra´m, R.J., Bavorova´, H., Ocˇadlı´ kova´, D., Cˇerna´, M., Sˇvandova´, E., 1998. Spontaneous level of chromosomal aberrations in peripheral blood lymphocytes of control individuals of the Czech Republic. Toxicol. Lett. 96/97, 137–142. Ro¨ssner, P., Bavorova´, H., Ocˇadlı´ kova´, D., Sˇvandova´, E., Sˇra´m, R.J., 2002. Chromosomal aberrations in peripheral lymphocytes of children as biomarkers of environmental exposure and life style. Toxicol. Lett. 134, 79–85. WHO/ECEH, 1996. Levels of PCBs, PCDDs and PCDFs in human milk. Second round of WHO-coordinated exposure study. Environmental Health in Europe Series 3, 121pp.
Int. J. Hyg. Environ.-Health 210 (2007) 495–499 www.elsevier.de/ijheh
Human biomonitoring system in the Czech Republic Milena Cˇerna´a,b,, Ve˘ra Spe˘va´cˇkova´a, Andrea Bata´riova´a,b, Jirˇ ı´ Sˇmı´ da, Ma´ja Cˇejchanova´a, Dana Ocˇadlı´ kova´a, Hana Bavorova´a, Bohuslav Benesˇ a, Ru˚z˘ena Kubı´ nova´a National Institute of Public Health, Centre of Environmental Health, Sˇroba´rova 48, 10042 Prague 10, Czech Republic Charles University, 3rd Faculty of Medicine in Prague, Czech Republic
a
b
Abstract The human biomonitoring (HBM) is an integral part of Environmental Health Monitoring System in the Czech Republic since 1994. Selected biomarkers of the internal dose (heavy metals, PCBs) and cytogenetic analysis of peripheral lymphocytes as a biomarker of the exposure/effect to/of environmental genotoxic factors are systematically followed up in the blood and urine of adults (blood donors), in children aged 8 to 10 years, and in the breast milk of nursing mothers. Selected outputs documented the declining trend of blood lead levels, with the recent reference value of 80 mg/l for men, and the rising trend of blood selenium levels in adults, but not in children. PCBs and chlorinated pesticides in human milk show a long-term downward trend, but still higher than in neighbouring countries. The frequency of aberrant cells revealed a downward trend, but the increase obtained in the last monitored period needs to be explained. Further HBM activities are required to demonstrate the corresponding trends and to reduce human exposure and health risks. r 2007 Elsevier GmbH. All rights reserved. Keywords: Human biomonitoring; Czech Republic; Heavy metals; PCBs; Chromosomal aberrations
Introduction The Environmental Health Monitoring System (EHMS) in the Czech Republic based on Govt. Decree No. 369/1991 has been run routinely since 1994 and includes altogether eight subsystems oriented on health risks of environment and health interactions (www.szu.cz, Kliment et al., 2000). The aim of EHMS is to provide the data that (a) are necessary for adopting a national policy of health and environmental protection, (b) provide the background for legislative measures Corresponding author. National Institute of Public Health, Centre of Environmental Health, Sˇroba´rova 48, 10042 Prague 10, Czech Republic. Tel./fax:+420 267082378. E-mail address: [email protected] (M. Cˇerna´).
1438-4639/$ - see front matter r 2007 Elsevier GmbH. All rights reserved. doi:10.1016/j.ijheh.2007.01.005
to be taken, (c) are linked to the environmental data obtained in the integral monitoring system, (d) help establish the threshold values and control their effectiveness, (e) enable to follow-up the long-term time trends and (f) facilitate international comparison of environmental health data. From the beginning human biomonitoring (HBM) represents an integral part of EHMS with the aim to assess the exposure of the Czech general population to a broad spectrum of environmental contaminants monitored in other environmental media including the diet. The main objectives of HBM are (a) to document the extent, the distribution and the determinants of exposure to important environmental pollutants by means of proper biomarkers of exposure and/or effects, (b) to follow-up long-term time trends, (c) to establish reference values for the Czech population
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
496
the National Institute of Public Health in Prague. A standardized operational protocol is used for sampling, labelling, transport and storage of human body fluids and tissue samples with special respect to the selected biomarkers. The selection of pollutant classes that are followed up in the body fluids and tissues was based on their measurement in the diet, air and drinking water within the EHMS, on their potential influences on human health, probability of population exposure and availability of health-relevant biomarkers to measure the internal dose or biological effective dose. Cytogenetic analysis of human peripheral lymphocytes was selected as a biomarker of exposure/effect to environmental genotoxic factors for both adults and children. Biomarkers were chosen on the basis of the availability of human body fluids sampling procedures in children and adults, likewise analytical methods that are well proven and suitable to analyze a large number of samples, and the accessibility of accredited laboratories equipped with advanced technique and skilled personnel have been considered. The broad spectrum of biomarkers exposure measured in human body fluids and tissues of the Czech general population is summarized in Table 1. Analysis of selected biomarkers is carried out according to the matrix/analytes using validated methods in laboratories accredited by the Czech Institute of Accreditation. The laboratories use reference materials, control samples and blanks, and participated in international comparative studies.
and (d) to generate information for strategies of exposure prevention and restriction. In this paper, we briefly describe the scenario of HBM in the Czech Republic and selected outputs. The data obtained are published on an ongoing basis.
Materials and methods In the period 1994–2003, HBM was conducted in four urban/suburban areas; two of them (Plzenˇ, U´stı´ n.L.) with a higher level of industrialization and traffic load, the remaining two (Benesˇ ov, Zˇd’a´r n.S.) represent more rural areas. Since 2005, the monitored urban areas with a potential of increased exposure include the capital Prague and Ostrava in northern Moravia; the less polluted urban areas are Liberec, Krome˘rˇ ı´ z˘ and Uherske´ Hradisˇ te˘. Only residents for a period of not less than 2 years in selected urban areas are included in the survey. Blood and urine samples are obtained from healthy adult blood donors aged 18–58 years and children aged 8–10 years, Breast milk samples are obtained from nursing mothers (preferentially primiparae) according to the WHO protocol (WHO/ECEH, 1996). Each year, about 100 subjects from each population group and urban area are selected. Informed consent is obtained from each sampled person or from the parents of sampled children. A short questionnaire is used to obtain information on age, weight, height, and stay in the locality, medication, occupational exposure and lifestyle habits, above all smoking. The HBM survey has been approved by the ethical committee of Table 1.
Matrices and analytes followed in the Czech HBM
Population
Matrix
Analytes
Adults–blood donors aged 18–58 years
Blood
Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se. Zn) Cytogenetic analysis of the peripheral lymphocytes Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs) Ochratoxin A Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn, I) Creatinine Cotinine (since 2005)
Blood serum
Urine
Children aged 8–10 years
Blood
Hair
Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn) Cytogenetic analysis of the peripheral lymphocytes Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn, I) Creatinine Cotinine (since 2005) Selected toxic and benefit elements (Cd, Hg, Pb, Cu, Se, Zn)
Children aged 5–6 years
Deciduous teeth
Pb
Nursing mothers
Breast milk
Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs)
Autopsies
Subcutaneous fat
Selected persistent chlorinated organic pollutants (PCBs, DDT/ DDE, HCB, HCHs)
Urine
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
497
of results below the LOD was greater than 50%, the descriptive statistics were not calculated. The 95th percentile levels and appropriate confidence intervals are used for reference values proposal.
Statistics The results in the form of descriptive statistics are expressed in mg/l (blood), mg/g creatinine (urine), mg/g (hair, teeth) and mg/kg fat (breast milk, subcutaneous fat). Data were processed using the statistical software packages Unistat 5.1 and Statistica version 7. For the statistical calculation, the data below the limit of detection (LOD) of the method used were replaced by a value equal to one-half of the LOD. If the proportion
Selected results Each year, the description of yearlong HBM activity results in the form of descriptive statistics, and inter-
60
50
49
Males
Females
Boys
Girls
49 44
45
44
40
40
38 36 34
34
µg / L
32 30
30
30
29
30
27
35
34
33
32 28
27
25 22
20
10
0
1996
1997
1998
1999 2000 Years
2001
2002
2003
Fig. 1. Blood-lead levels in monitored adults and children (median, mg/l). 180
160 Median
25% - 75%
5% - 95%
140
µg /l
120
116
100 91
92
2000
2001
89
80
89
79
73
70
60
40
20
1996
1997
1998
1999
2002
Years
Fig. 2. Blood selenium level in monitored adults (mg/l).
2003
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
498
in 1996/98 was assessed to be 95 mg/l (Cˇerna´ et al., 2001), and 80 mg/l in 2003/04 (Bata´riova´ et al., 2006). In children, the B-Pb median values are about 30 mg/l with no significant trend in time; only 0.8% (n ¼ 12) of monitored children had elevated B-Pb levels above 100 mg/l. Blood cadmium levels in non-smokers are about 3 times lower than in smoking adults; the levels in urine are higher in women that in men (Puklova´ et al., 2005). In children, the blood and urine concentrations
pretation data are indicated in the Technical and Summary Annual Reports and on the web sites of the National Institute of Public Health (www.szu.cz). Only selected results as output examples are presented here. Blood lead levels (B-Pb) in adults are higher in men that in women and have declined significantly during the monitoring period (Fig. 1) with only 0.9% (n ¼ 28) of values above the health relevant HBM limit of 150 mg/l (Ewers et al., 1999). The reference value for male adults
800
700 Median
25% - 75%
5% - 95%
600
µg / kg fat
500
400 352 323
300 201
200
165
165
174
168
164
139
137
100
0
1994
1995
1996
1997
1998 1999 Years
2000
2001
2002
2003
Fig. 3. Time-related levels of PCB indicator congener in breast milk.
1.8 1.65
1.6 1.4
Adults 1.4 1.29
1.26
1.23
1.2
1.14 1.06
1.04
% AB.C.
Children
1
1.1
0.92
0.8 0.6 0.4 0.2 0 1994
1995
1996
1999
2001
2003
Years
Fig. 4. Frequency of chromosomal aberrations in the monitored children and adults.
ARTICLE IN PRESS M. Cˇerna´ et al. / Int. J. Hyg. Environ.-Health 210 (2007) 495–499
are mostly below the detection limit of the method used. Blood selenium levels in adults increased significantly with time being consistent with a similar upward trend of selenium in the diet (Fig. 2) (Bata´riova´ et al., 2005). Polychlorinated biphenyls (PCB) and chlorinated pesticides measured in breast milk show a long-term declining trend (Fig. 3) (Cˇerna´ et al., 2003). Reference values for PCB 153 congener in 1994/95 (700 ng/g fat) was about twice as high as for breast milk in the German Survey of 1990/92 (Ewers et al., 1999), whereas the comparable reference value for the Czech population (330 ng/g fat) was obtained in 2002/03 only. Cytogenetic analysis of human peripheral lymphocytes has been used in the Czech Republic since 1974 to assess occupational exposure to clastogenic chemicals (Ro¨ssner et al., 1998) and we suppose that this biomarker might be used as a biomarker of environmental pollution. The frequency of aberrant cells markedly decreased within the monitored period 1994–2001 in both, children (Ro¨ssner et al., 2002) and adults. However, an increase in the level of chromosomal aberrations was observed in adults in the last monitored period (2003) when children were not sampled (Fig. 4).
Conclusion Biomonitoring assessment of the exposure of the Czech population represents an important part of risk assessment and risk management process. The levels of most, but not all monitored biomarkers of exposure show a gradual decline in time reflecting the effectiveness of preventive measures on the improvement of environmental pollution and lifestyle habits. Reference values can be used to identify population subgroups or individuals with an increased level of exposure. Further monitoring is required in order to establish an adequate database to demonstrate trends, and to reduce human exposure and health risks.
499
References Bata´riova´, A., Cˇerna´, M., Spe˘va´cˇkova´, V., Cˇejchanova´, M., Benesˇ , B., Sˇmı´ d, J., 2005. Whole blood selenium content in healthy adults in the Czech Republic. Sci. Total Environ. 338, 183–188. Bata´riova´, A., Spe˘va´cˇkova´, V., Benesˇ , B., Cˇejchanova´, M., Sˇmı´ d, J., Cˇerna´, M., 2006. Blood and urine levels of Pb, Cd and Hg in the general population of the Czech Republic and proposed reference values. Int. J. Hyg. Environ. Health 209, 359–366. Cˇerna´, M., Spe˘va´cˇkova´, V., Benesˇ , B., Cˇejchanova´, M., Sˇmı´ d, J., 2001. Reference values for lead and cadmium in blood of Czech population. Int. J. Occup. Med. Environ. Health 14, 189–192. Cˇerna´, M., Sˇmı´ d, J., Svobodnı´ k, J., Grabic, R., Crhova´, Sˇ., Kubı´ nova´, R., 2003. Monitoring of selected polyhalogenated hydrocarbons in breast milk: Czech Republic, 1994 to 2001. FEB 12 (2), 203–207. Ewers, U., Kraus, C., Schulz, Ch., Wilhelm, M., 1999. Reference values and human biological monitoring values for environmental toxins. Int. Arch. Occup. Environ. Health 72, 255–260. Kliment, V., Kubı´ nova´, R., Kazmarova´, H., Kratzer, K., Sˇisˇ ma, P., Ruprich, J., Cˇerna´, M., Gregu˚rkova´, M., 2000. Five years of the system of monitoring the environmental impact on population health of the Czech Republic. Central Eur. J. Publ. Health 8, 198–205. Puklova´, V., Bata´riova´, A., Cˇerna´, M., Kotlı´ k, B., Kratzer, K., Melichercˇı´ k, J., Ruprich, J., Rˇehu˚rˇ kova´, I., Spe˘va´cˇkova´, V., 2005. Cadmium exposure pathways in the Czech urban population. Central Eur. J. Publ. Health 13 (1), 11–19. Ro¨ssner, P., Sˇra´m, R.J., Bavorova´, H., Ocˇadlı´ kova´, D., Cˇerna´, M., Sˇvandova´, E., 1998. Spontaneous level of chromosomal aberrations in peripheral blood lymphocytes of control individuals of the Czech Republic. Toxicol. Lett. 96/97, 137–142. Ro¨ssner, P., Bavorova´, H., Ocˇadlı´ kova´, D., Sˇvandova´, E., Sˇra´m, R.J., 2002. Chromosomal aberrations in peripheral lymphocytes of children as biomarkers of environmental exposure and life style. Toxicol. Lett. 134, 79–85. WHO/ECEH, 1996. Levels of PCBs, PCDDs and PCDFs in human milk. Second round of WHO-coordinated exposure study. Environmental Health in Europe Series 3, 121pp.