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Tissue concentrations of mercury were determined by cold vapor atomic absorption spectrometry in different inbred mouse strains after continuous treatment with HgCl2 (3 weekly sc injections of 0.5 mg/kg bw) for up to 12 weeks. Except for the thymus, in which steadily increasing mercury concentrations were found, in steady state levels of mercury were reached in blood and liver after 4 weeks and in spleen and kidney after 8 weeks. In the closely related strains C57BL/6, B10.D2, and B10.S, which differ only or primarily at the major histocompatibility complex, mercury concentrations in blood and liver were about twofold lower and renal concentrations were about three- to fivefold lower than those detected in strains A.SW and DBA/2. Another strain difference was observed in the spleen: after 8 and 12 weeks of continuous HgCl2 treatment, mercury concentrations in the spleen of strains A.SW, C57BL/6, and B10.S were significantly higher than those in strains DBA/2 and B10.D2. The strain difference in the spleen, an organ of the immune system, correlates with the susceptibility to the HgCl2-induced systemic autoimmune syndrome in mice in that the strains showing a higher mercury accumulation in the spleen are susceptible to this form of chemically induced autoimmunity, whereas the strains with lower mercury concentrations in the spleen are resistant.

The levels of lead and cadmium were determined in deciduous teeth (incisors only) of children living in Stolberg and some other cities located in North-Rhine-Westfalia, Germany. The Stolberg children were born in 1968-1973 (group 1; n = 103) and 1982/1983 (group 2; n = 103). The other children (n = 109) were born between 1979 and 1986. All teeth were analysed within the same analytical series by atomic absorption spectrometry (AAS). The results show that the average levels of lead and cadmium in milk teeth have decreased significantly in the time period from 1970 to 1990. Considering the Stolberg children the fall of tooth lead was about 50% and the fall of tooth cadmium was about 60%. Children from other cities show a comparable decrease of tooth lead and tooth cadmium. The results indicate that a significant decrease of the lead body burden and cadmium body burden of children and probably also of the general population of Germany has occurred during the last years.

Within a larger comparative environmental health screening program in East and West Germany neurobehavioral and neurophysiological measures were taken in 367 six year old children in Leipzig (N = 179), Gardelegen (N = 68), and Duisburg (N = 120). Lead concentrations from venous blood samples (PbB) and from deciduous teeth (PbT) were measured as markers of environmental lead exposure by electrothermal AAS. Dependent variables included four subtests from NES1 (tapping, reaction time, pattern comparison, and Benton visual retention), as well as VEP-latencies (N2, P100, N3) evoked by checkerboard patterns of different size and contrast. The overall median blood lead-concentration was 5 micrograms/dl (range: 1.3-19.0 micrograms/dl), and the corresponding tooth lead-concentration was 2 micrograms/g (0.2-14 micrograms/g). The 95-percentile of the overall frequency distribution for PbB was below 10 micrograms/dl. Associations between markers of lead-exposure and neurobehavioral or neurophysiological outcome were assessed by means of multiple linear or logistic regression analyses. After adjusting for relevant confounders/covariates significant (p < 0.05) Pb-related deficit was found for tapping and pattern recognition with respect to PbB but not PbT. No such associations could be established for VEP-latencies. These results are compatible with the hypothesis that subtle neurobehavioral dysfunction in children may be associated with very low PbB.

The electroretinogram (ERG) of rhesus monkeys was re-examined more than 2 years after termination of lead exposure when mean blood lead levels had declined to values below 10 micrograms dl-1. Amplitude of the b-wave was increased by lead exposure at scotopic conditions, while there were no changes in photopic signals. The lead-induced effects were similar to alterations detected during the treatment phase and, thus, are not dependent on current exposure. Taking into account, that dopamine antagonists cause similar changes in the ERG, it is suggested that the observed effects may be mediated by a permanent change of dopaminergic processes since immunoreactivity also revealed adverse effects on the dopaminergic system in the retinae of these monkeys.

Cadmium, lead and zinc were determined in garden soils and vegetable products from private gardens located in a lead/zinc smelter area (Stolberg, Germany). At the same time lead and cadmium were measured in blood and urine samples collected from 90 garden owners. Inspite of extraordinary high levels of cadmium and lead in garden soils and vegetables, blood lead, blood cadmium and urine cadmium levels were not or only slightly elevated in the gardeners when compared to a reference group of subjects from the same area who did not consume home-grown vegetables and fruits. The results show that high levels of pollutants in soil and vegetables are not necessarily associated with an increased burden of pollutants in the human body, and that the transfer of pollutants from soil to humans might have been overestimated in some cases. Moreover, the results underline the preventive character of the guideline values presently applied with respect to the evaluation of soil contaminants.

In 1989, blood lead and blood cadmium levels were determined in 229 children (age 6-7 years) living at Stolberg (West Germany). The area of Stolberg is heavily polluted by lead and other toxic metals due to emissions from a large primary lead smelter. The mean blood lead level was 6.3 micrograms/dl (range 2.6-15.5 micrograms/dl) and the mean blood cadmium level was 0.14 microgram/l (range less than 0.1-0.5 microgram/l). The blood lead levels were affected by the following factors: living in the central urban area with high lead levels in dust fall-out; living in a family of foreigners; involuntary inhalation of smoke at home; living in a family with a family member employed in the lead industry. Children from foreign families also had higher blood cadmium levels than children from German families. However, inhalation of tobacco smoke did not affect the blood cadmium levels. In total, there has been a significant decline of blood lead and blood cadmium levels among children from the Stolberg area since 1982.

Blood lead levels were determined in 3098 55-66 year-old women living in different areas of Northrhine-Westphalia (F.R.G.). Blood cadmium levels were determined in a subgroup of 2538 women. The studies were performed between 1982 and 1988. The results show that there has been a further fall of blood lead levels in the general population of West-Germany since the CEC blood lead surveys of 1979 and 1981. A comparable reduction of blood cadmium was not noted. Residents of large urban agglomerations had, on average, slightly higher blood lead levels than residents of small cities located in rural areas (+0.2-0.5 microgram/dl). With regard to blood cadmium, no differences were seen. Smokers were found to have, on average, 3-4 times higher blood cadmium levels than non-smokers. Blood lead was also elevated in smokers when compared to non-smokers. The highest blood lead levels recorded were in the range of 15-30 micrograms/dl. The data further suggest that lead mobilization during conditions of bone demineralization, e.g. in cases of osteoporosis, does not result in toxic blood lead levels in postmenopausal women.

Shed deciduous teeth (incisors only) were collected from children (n = 199) living in Duisburg and Gummersbach (F.R.G.) in 1976 and 1988. The teeth were analysed for lead and cadmium. Considering all teeth, there was a significant of tooth lead and tooth cadmium from 1976 to 1988. The reduction was between -40 and -50% for tooth lead and -45% for tooth cadmium. Regarding tooth lead, the reduction was more pronounced in children from Duisburg, an area heavily polluted by lead and other heavy metals due to the presence of large iron and steel plants and a large lead-/zinc smelter. Teeth from the upper jaw were found to have higher lead and calcium concentrations than teeth from the lower jaw. Moreover, it was found that central incisors had higher lead and cadmium concentrations than lateral incisors. Even after the effects of jaw and tooth type had been allowed for, the reduction of tooth lead and tooth cadmium could be demonstrated. Children living in pre-war houses were found to have higher tooth lead and tooth cadmium levels than children living in post-war houses. The higher lead and cadmium burden of children living in old houses seems to be related to a higher degree of exposure to lead and cadmium via drinking water resulting from the release of these metals from old zinc-plated steel water pipes. In total, our results indicate that there has been a significant decrease of lead and cadmium exposure in West-German children since the mid-70s. The reduction of tooth lead levels parallels the decrease of blood and bone lead levels, which has been observed in previous studies.