8. RESULTS OF SUBSYSTEM 5: HEALTH EFFECTS OF EXPOSURE TO TOXIC POLLUTANTS FROM THE ENVIRONMENT, BIOLOGICAL MONITORING

8.1 Organization of monitoring activities

This Subsystem includes the monitoring of toxic substances or their metabolites (biomarkers of internal dose), and selected biological alterations (biomarkers of biological effect) in the biological material of three population groups: adults, children (8–10 years old) and post-puerperal mothers in four selected regions: Benešov, Žďár n. Sázavou, Plzeň, and Ústí n. Labem. In each region, 100 subjects from each population group under follow-up have been included into the study. Basic demographic data and information on lifestyle necessary for estimate the population exposure to the contaminants have been collected by a brief questionnaire. The subsystem is supplemented with the monitoring of the mutagenic activity of particulate matter, fraction PM10, in the ambient air.

Inter-laboratory differences have been minimized by defining of analyses according to matrix or analyte, respectively. After the tender in 2000, the external co-operating facility where the analyses of PCBs and other organic compounds in breast milk were provided was replaced. The results obtained are presented for the particular population groups as summary data from all the localities under monitoring in the form of basic descriptive statistics.

Mostly, the limits for the toxic substances content in human biological materials have not been established for non-professionally exposed population. However, for some serious contaminants, so-called maximum tolerable levels have been determined. The exceeding of these values signalize potential risk to population health. The homogeneity of the data produced and their compatibility with the data found in analogous foreign studies along with a several-year continuity of the Monitoring System allow their application for determination of reference values characterizing the burden of the population. A certain extent of individual variability may be caused by differences in the magnitude of exposure and the individual sensitivity of the human organism to the environmental pollution.

8.2 Monitored factors

Toxic metals (cadmium, mercury, lead), as well as selected beneficial trace elements (copper, selenium, zinc) were included among the factors monitored in 2001. They were determined in the blood of adults, in the blood and hair of children. Urine was not sampled in 2001. Lead concentrations were also measured in the teeth of children, and cadmium concentrations in kidney tissue. Persisting chlorinated organic substances (indicator congeners of polychlorinated biphenyls – PCBs, and selected chlorinated pesticides) were analyzed in breast milk and subcutaneous fat. Dioxins (PCDDs), dibenzofurans (PCDFs) and PCB congeners with dioxin activity were also analyzed in the same samples of subcutaneous fat. The results are expressed as the total toxic equivalent value (TEQ). The population under follow-up was investigated for chromosomal aberrations in peripheral lymphocytes. Concerning the environmental genotoxicity, the bacterial mutagenicity of particulate matter (PM10 fraction) in the ambient air was monitored.

8.2.1 Toxic metals and trace elements

Summarized results are presented in the form of basic descriptive statistics in Table 8.1. The values found are generally consistent with both the data presented for other non-professionally exposed population groups in the literature and the data derived from the previous monitoring activities.

The blood lead level with a median value of 36.0 µg/L in adults is within the range of reference values established in the industrialized countries and is in agreement with findings in previous years (Fig. 8.1a). In 90 % of the adult population the lead blood level does not exceed the value of 67.0 µg/L. The lead content in the blood depends on gender with significantly higher values (p < 0.001) in males (median 40.0 µg/L) than in females (median 28 µg/L) (Fig. 8.2a). The critical (tolerable) value of 100 µg/L was exceeded in 6 subjects (1.5 %) of the adult population. The blood lead level (median) in children was 31.0 µg/L, the 90th percentil did not exceed 46.0 µg/L. The value of 100 µg/L was exceeded in 3 children (0.9 %); 70 % of the values are in the range of 20–40 µg/L (Fig. 8.2d). The findings are in agreement with reference values estimated on the basis of results of the Monitoring System in the period 1996–2000 concerning the Czech population, i.e. 95 µg/L (males), 80 µg/L (females) and 60 µg/L (children).

The blood cadmium level is a biomarker of the current exposure of the population and is strongly influenced by the smoking habit. The median value in the adult population is 0.6 µg/L (in smokers, N = 138, median 1.7 µg/L; non-smokers, N = 260, median 0.45 µg/L). It is in agreement with results of monitoring in preceding years (Fig. 8.1b). The blood cadmium level in child population is in more than 50 % (65 %) in the whole series below the detection limit. The estimate of reference values of cadmium in the blood for the Czech population following from results of the Monitoring System in 1996–2000 is 1.2 µg/L in adults and 0.6 µg/L in children. Cadmium was also analyzed in kidney tissue; median value of 15.3 mg/kg was found from a total of 16 samples which corresponds with the results from preceding years (median 18.5 mg/kg of tissue in 1999 and 2000).

Mercury levels in the blood do not signalize any increased burden in the Czech population; in 2001, they were below the reference values 2.8 µg/L in adults and 1.6 µg/L in children estimated for the Czech population on the basis of results from the Monitoring System in the period 1996–2000.

Blood copper level (Fig. 8.1c) is in agreement with both generally presented reference values and reference values estimated for the Czech population on the basis of the Monitoring System results from the period 1996–2000. They are in the range of 970 µg/L (males) to 1450 µg/L (females), for children 1350 µg/L. The results do not indicate any hyposaturation of the Czech population. Significantly higher values demonstrated in females are physiological (Fig. 8.2b).

Selenium is considered to be an element with beneficial effects and its antioxidant potential plays a role in protective mechanisms against oxidation stress and resulting disorders promoted by that process (cancer, cardiovascular diseases). The blood selenium level is an indicator of saturation with this element. Concentration in the range of 70 to 100 µg/L is considered to be optimal. Results obtained during the monitoring activities reveal a gradually increasing trend, in 2001, the median content in adult population was 91.5 µg/L; in children the values are lower (median 66.0 µg/L (Fig. 8.1e). More than 50 % of the samples are in the range of 80–100 µg/L (Fig. 8.2c).

Blood zinc level is in the relation with that found in previous monitoring periods and with reference values estimated for the Czech population, as well, which are in the range of 8575 µg/L (males), 8431 µg/L (females) and 7134 µg/L in children (Fig. 8.1d).

Results of elemental analyses in children’s hair and of lead in children’s teeth show stable data in agreement with results obtained in preceding years.

8.2.2 Toxic substances of organic origin

Summary results are presented in the form of descriptive statistics in Table 8.2. The monitoring of PCB indicator congeners in breast milk has confirmed the dominance of congeners 138, 153 and 180, which persist in the organism for long time. However, singular high values in the series indicate the existence of individual local burden points. More than 50 % of other PCB congeners values are below the detection limit. Results of statistics analysis for the whole period of monitoring (1994–2001) indicate a significant content increase with the mother’s age, independence of the chronological order of parturition, and a significant decrease with time (Fig. 8.3a). Higher values have been found in the region of Ústí n. Labem.

Values of chlorinated pesticides (hexachlorobenzene, sum of DDTs) in breast milk show declining trend of these substances (Fig. 8.3b). For technical reasons the values of DDTs will be presented together with those for 2002.

The toxic PCB congeners together with PCDDs, PCDFs were analyzed in samples of subcutaneous fat, too. In the period 2000–2001, a total of 29 samples were analyzed. Results confirm that PCBs with dioxin activity participate more than 60 % in the overall toxic equivalent value TEQ, the median value of which is 56 pg/g of fat. The significant quotient of toxic PCB congeners in the total toxicity expressed by the value of TEQ is illustrated in Fig. 8.4.

Mycotoxin ochratoxin A level in blood serum was below the detection limit in 70 % of kidney tissue samples analyzed.

8.3 Cytogenetic analysis of peripheral lymphocytes

Due to the time-demanding character of cytogenetic analyses, the results for 2001 will be presented in the Special and Summary Reports for 2002.

8.4 Genotoxic effects of ambient air

Systematic monitoring of the mutagenic activity of airborne particulate matter (PM10) started at the end of 1996 and has been carried out continually at 18-day intervals since 1997 in extension of the sampling of polycyclic aromatic hydrocarbons (PAHs) within Subsystem I. In view of the significantly higher values demonstrated in winter months, sampling was performed in two periods in 2001: January–March and October–December. In 1999, monitoring of PAHs was terminated in Benešov and replaced by Prague. In 2001, results of mutagenicity in both tester strains of the bacterium Salmonella Typhimurium, TA98 and its derivative YG1041, signalize a rising trend with the highest values in Prague (Fig. 8.5a). The mutagenic activity of all samples, expressed by the number of revertants per m3 of air, correlated with the analyses results of PAHs (the sum of PAHs, the TEQ value, and the concentration of benzo[a]pyrene) conducted within the framework of Subsystem I. The results of mutagenic activity detected in the tester strain YG1041 signalize the increasing concentration of other chemical structures with mutagenic potential bound to particulate matter, namely nitroarenes.

8.5 Partial conclusions

Biomarker levels are generally characterized by substantial inter-individual variability but they are indicative for the population exposure in general. In 2001, by comparison of the results of biological monitoring with the existing reference or critical values and the data of similar studies, it can be stated that the xenobiotic burden of the Czech population is generally consistent with the mean values within the frame of the European countries average. There was confirmed a declining tendency in cadmium concentrations and an altogether sufficient saturation with selenium. The PCB indicator congeners content in breast milk indicates, from the point of view of long-term temporal trends, a decreasing trend with considerable inter-individual variability and potential local differences in the burdening of the population. Analyses of PCDDs, PCCDFs and PCBs with dioxin activity in subcutaneous fat have confirmed that PCBs represent more than 60 % of the TEQ value. A slow continuous decrease of hexachlorobenzene in breast milk was observed. The results of mutagenic activity of the airborne particulate matter (PM10), signalize a general upward trend and confirm higher values in samples taken in Prague.

Table 8.1 Content of metals and metaloids in human biological material, 2001

Number of measurements (N), Median (Me), 90th percentile (P90), Range of medians from all of the monitored cities (Benešov, Plzeň, Ústí n.L, Žďár n.S)

Biological material

Dimension

Cadmium

Lead

Mercury

Copper

Selenium

Zinc

Chromium

Adults
blood

N

µg/l

398

400

400

400

400

400

 

Me

0.6

36

0.82

900

91.5

6 700

 

P90

2.73

67

2.31

1 178

109

8 213

 

Range

0.5–0.7

29–46

0.68–1.3

895–910

88.7–94

6 360–7 110

 

Children
blood

N

µg/l

 

338

354

338

338

338

 

Me

DL

31

0.42

975

66

5 250

 

P90

 

46

1.07

1 165

80

6 624

 

Range

 

28–35

36–44

925–1 013

64–68

5 000–5 450

 

Children
hair

N

µg/g

344

344

325

344

344

344

344

Me

0.12

1.3

0.2

10

0.21

118

0.16

P90

0.34

3.2

0.55

35

0.33

164

0.33

Range

0.09–0.16

1.0–1.5

0.13–0.34

9.0–13

0.20–0.22

110–135

0.14–0.21

Children
teeth

N

µg/g

 

142

 

 

 

 

 

Me

 

0.95

 

 

 

 

 

P90

 

1.9

 

 

 

 

 

Range

 

0.87–1.1

 

 

 

 

 

Note:
DL: > 50 % of the values under detection limit

Table 8.2 Content of organic compounds in human biological material, 2001

Number of measurements (N), Median (Me), 90th percentile (P90), aRange of medians from all the monitored cities (Benešov, Plzeň, Ústí n.L, Žďár n.S)

Biological material

Dimension

HCB

DDTs

PCB138

PCB153

PCB180

Breast milk

N

µg/kg fat

398

389

389

389

389

Me

122

421

100

139

78

P90

269

745

188

273

162

Rangea

114–138

364–493

86–108

120–152

73–84

 

Dimension

PCDDs

PCDFs

PCBs

TEQ total

Subcutaneous fat*

N

pg TEQ/g fat

29

29

29

29

Me

8.4

13.4

33.7

55.5

Range of individ. values

4.5–21.9

5.7–78.1

18.5–137.6

28.7–238

* values from the year 2000 and 2001

Fig. 8.1a Blood lead level, 1994–2001
Fig. 8.1b Blood cadmium level, 1994–2001
Fig. 8.1c Blood copper level, 1994–2001
Fig. 8.1d Blood zinc level, 1994–2001
Fig. 8.1e Blood selenium level, median concentration, 1994–2001
Fig. 8.2a Blood lead level distribution in adults, 2001
Fig. 8.2b Blood copper level distribution in adults, 2001
Fig. 8.2c Blood selenium level distribution in adults, 2001
Fig. 8.2d Blood lead level distribution in children, 2001
Fig. 8.3a Polychlorinated biphenyls in breast milk, median concentration, 1994–2001
Fig. 8.3b Selected chlorinated organic pesticides in breast milk, median concentration, 1994–2001
Fig. 8.4 Proportion of compounds with dioxin effect on the toxic equivalent (TEQ) in subcutaneous fat, 2000 and 2001
Fig. 8.5a Mutagenicity of airborne particulate matter, fraction PM10, winter season 2001
Fig. 8.5b Trend of urban air mutagenicity

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