System of monitoring the environmental impact on population health of the Czech Republic.

The data collected in the System of monitoring the environmental impact on population health of the Czech Republic in 1994 and 1995 were obtained routinely and in a stabilized manner in six subsystems: health consequences and risks related to air pollution, drinking water quality, noise, human dietary exposure, human exposure to toxic pollutants from the environment and the monitoring of the health state and evaluation of selected indicators of demographic and health statistics. They represent a useful and comprehensive background for providing objective information on the health status of the Czech population and on pollution of different components of the environment in the Czech Republic to other countries in Europe and worldwide to facilitate their commercial and cultural contacts. The results of the calendar year 1995 show that no critical situation needing urgent countermeasures to be taken appeared in the localities monitored. However, some results are indicative of the necessity to take certain remedial measures to maintain all population exposure burdens as low as reasonably possible from the economical and social points of view. The set of problems was identified as important also in 1994. Generally, the limit values and exposure standards are exceeded only sporadically in some localities while for most contaminants monitored only very low values compared to the admissible limits can be found.

Biological monitoring of child lead exposure in the Czech Republic.

The area around the Pribram lead smelter has been recognized to be heavily contaminated by lead (Pb). In the early 1970s, several episodes of livestock lead intoxication were reported in this area; thereafter, several epidemiological and ecological studies focused on exposure of children. In contrast to earlier studies, the recent investigation (1992-1994) revealed significantly lower exposure to lead. From 1986-1990, recorded average blood lead levels were about 37.2 micrograms lead (Pb)/100 ml in an elementary school population living in a neighborhood close to the smelter (within 3 km of the plant). The present study, however, has found mean blood lead levels of 11.35 micrograms/100 ml (95% CI = 9.32; 13.82) among a comparable group of children. In addition to blood lead, tooth lead was used to assess exposure among children. Statistically significant differences (p < 0.05) were observed between the geometric mean tooth lead level of 6.44 micrograms Pb/g (n = 13; 95% CI = 3.95; 10.50) in the most contaminated zone and 1.43 micrograms Pb/g (n = 35; 95% CI = 1.11; 1.84) in zones farther away from the point source. Both biomarkers, blood and tooth lead levels, reflect a similar pattern of lead exposure in children. This study has attempted a quantitative assessment of risk factors associated with elevated lead exposure in the Czech Republic. Content of lead in soil, residential distance from the smelter, consumption of locally grown vegetables or fruits, drinking water from local wells, the mother's educational level, cigarette consumption among family members, and the number of children in the family were factors positively related (p < 0.05) to blood lead levels. The resulting blood lead level was found to be inversely proportional to the child's age.

Renal effects in children living in the vicinity of a lead smelter.

A cross-sectional study was carried out to determine whether environmental exposure of children to lead may cause renal effects. The study involved a total of 195 children aged 12 to 15 years. One hundred forty-four children (63 boys and 81 girls) were recruited from two schools in the vicinity of a lead smelter and 51 (25 boys and 26 girls) from a school in a rural area. Compared to their referents, boys and girls from the two schools in the polluted area had significantly higher levels of lead in blood (PbB) but similar levels of cadmium (CdB) and zinc protoporphyrins (ZPP). The functional integrity of the kidney was assessed by measuring the urinary excretion of beta 2-microglobulin, Clara cell protein, retinol-binding protein (RBP), albumin and beta-N-acetyl-D-glucosaminidase. The most significant and consistent finding of the study was that children from the two schools in the polluted area showed a significant elevation of the urinary excretion of RBP that paralleled the level of lead in blood or in the dust collected on the school playgrounds. A similar pattern was observed for the prevalence of elevated values of urinary RBP which increased from 3.9% in the control area up to 17% in the most polluted school. Urinary RBP was found to be associated with PbB (partial r2 = 0.046, P = 0.005) in a stepwise regression analysis testing also the influence of age, sex, CdB, and ZPP. In conclusion, the present study suggests that lead contaminating the environment may cause slight effects on the proximal tubule function in children at exposure levels close to those associated with CNS deficit.

Relationship of blood protein levels to outdoor air pollutant concentrations in a semicohort of school-age children living in urban areas differing by quality of air.

Variations in some humoral immune responses to polluted air were studied in two semicohorts of children, initial age 10 years, from two urban communities differing from each other by the degree of ambient air pollution. The material for analysis (blood, saliva) was collected every autumn and spring in 3 successive years, giving a total of 6 sets of specimens for each examinee. All blood specimens were examined for the serum level of immunoglobulins (IgG, IgA, IgM), lysozyme (LYS), total serum protein (TP) and the level of the acute reactants alpha 2 macroglobulin (A2M), alpha 1 antitrypsin (A1AT), transferrin (TRF) and ceruloplasmin (CPL). The saliva specimens were examined for the level of lysozyme (sLYS) and secretory IgA (sIgA). The mean protein concentrations for each of the 6 sampling series were correlated with the mean of 24-h emission concentrations measured in the last 3 months preceding the autumn or spring sampling series. In the community area characterized by a low-degree non-industrial pollution of air the correlations of immunoglobulins to SO2 and floating particles (FP) in air were as a rule inversed while the response from TP, LYS and acute reactants was direct. In the community contaminated by industrial pollutants, correlations between proteins and SO2 were markedly weaker, but there was a significant positive correlation between H2S and levels of IgA and A2M in blood and sIgA and sLYS in the saliva. A high degree of positive correlation was also observed between H2S and levels of IgM and LYS. Inverse correlations were only between levels of LYS and FP, SO2 and H2S. Significant correlations were also between contaminant concentrations and FP. The associations found between the contaminant concentrations in air and levels of blood and saliva proteins supports the hypothesis that quality of air may have considerable impacts on defense mechanisms. Seasonal variations in the quality of air may increase the rates of childhood morbidity for acute upper respiratory tract infections.