Despite their long-term ban, persistent organochlorine compounds like hexachlorobenzene (HCB), p,p'-dichlorodiphenylethylene (DDE) as well as polychlorinated biphenyls (PCBs) are still of environmental concern. For the evaluation of potential occupational or environmental exposures to these substances, it is essential to know the current background burden of the general population. As representative and up-to-date information is missing for Germany, we have analysed a large dataset generated in studies on potential exposure to lower chlorinated PCBs to fill this gap for the levels of HCB, DDE as well as PCB 138, PCB 153 and PCB 180. We have investigated n=2750 plasma samples of persons of the general population living in North Rhine-Westfalia and Hesse aged 6-65 years and sampled between September 2010 and March 2014. For evaluation of the age-dependent accumulation in the general population we have generated seven age groups in the collective. Our laboratory used a validated and quality controlled procedure using GC/MS for quantification of the organochlorine compounds in plasma (LOQ: 0.01μg/L). The median (95th percentile) levels for ∑ PCB 138+PCB 153+PCB 180 were 0.14 (0.73); 0.30 (0.82); 0.38 (0.88); 0.50 (1.14); 0.92; 1.58 (3.54) and 2.41 (4.82)μg/L plasma in the age groups 6-10 years (n=102), 11-17 years (n=499), 18-25 years (n=157), 26-35 years (n=710), 36-45 years (n=400), 46-55 years (n=525) and 56-65 years (n=357), respectively. Similarly, the median (95th percentile) levels of p,p'-DDE were 0.18 (1.24); 0.18 (0.74); 0.24 (0.85); 0.30 (1.20); 0.45 (1.74); 0.64 (3.25) and 0.94 (4.7)μg/L plasma. Finally, the median (95th percentile) of HCB in plasma in these age groups was 0.05 (0.10); 0.06 (0.11); 0.08 (0.15); 0.08 (0.15); 0.11 (0.22); 0.14 (0.42) and 0.20 (0.68)μg/L plasma. Our results prove an overall substantial reduction in the body burden to organochlorine compounds in Germany compared to earlier studies. However, 15% and 3.6% of the examined collective exceeded the HBM-I- and HBM-II-values for PCBs established by the German Human Biomonitoring Commission. Due to a large sample size and a collection period from 2010 to 2014, our data might be suitable for the evaluation of additional exposures to these POPs and may serve as reference values.

In spring 2010, high internal exposures (up to 236 μg/L plasma) for the sum of indicator polychlorinated biphenyls (PCB) were discovered in workers in a transformer recycling company in Germany, where PCB-contaminated material was not handled according to proper occupational hygiene. The release of PCB from this company raised growing concerns regarding possible adverse human health effects correlated with this exposure. This provided a basis for a large biological monitoring study in order to examine the internal exposure to PCB in individuals working in that recycling company, their family members, and relatives, as well as subjects working or living in the surroundings of this company. Blood samples from 116 individuals (formerly) employed in the transformer recycling company and 45 direct relatives of these persons were obtained. Further, blood samples of 190 subjects working in close vicinity of the recycling plant, 277 persons working in the larger area, and 41 residents of the area were investigated. Plasma samples were analyzed for the 6 indicator PCB (PCB 28, 52, 101, 138, 153, 180) and 12 dioxin-like PCB using gas chromatography/mass spectroscopy (GC/MS; limit of detection [LOD] at 0.01 μg/L). Median concentrations (maximum) for the sum of the 6 indicator PCB in blood of the employees, their relatives, individuals working in close vicinity, persons working in the larger area, and the residents were 3.68 (236.3), 1.86 (22.8), 1.34 (22.9), 1.19 (6.42), and 0.85 (7.22) μg/L plasma, respectively. The (former) employees of the transformer recycling plant partly showed the highest plasma PCB levels determined thus far in Germany. Even family members displayed highly elevated levels of PCB in blood due to contaminations of their homes by laundering of contaminated clothes. Vicinity to the recycling plant including reported contact with possibly contaminated scrap was the main contributor to the PCB levels of the workers of the surrounding companies. Residents of the area did not show significantly elevated blood PCB levels compared to the general population. Our biomonitoring results served as a basis for individual risk communication and successful risk management.

Polychlorinated biphenyls (PCBs) are organochlorine pollutants with a worldwide dissemination. We examined telomere length (TL) in peripheral blood cells of 207 individuals with a high body burden of PCBs due to occupational exposure in a transformer recycling company. Whereas TL in granulocytes was not affected, the age-adjusted TL in lymphocytes (∆TL_Lymph) of exposed individuals was significantly shorter than expected [−0.77 kb; 95 % confidence interval (CI) −0.9316; −0.6052; p = 0.0001]. PCB exposure did not affect lymphocyte numbers or T cell receptor excision circle (TREC) levels in T cells, suggesting that PCBs cause loss of telomeric DNA in T cells due to their metabolic activation and antigen-stimulated proliferation. In support of this hypothesis, blood plasma levels of PCB-exposed individuals inhibited expression of telomerase, the telomere elongating enzyme in vitro in antigen-specific T cell proliferation assays. 3-OH-CB28, a downstream metabolite of the lower chlorinated PCB-28 in PCB-exposed individuals (mean blood plasma concentration: 0.185 ± 0.68 ng/mL), inhibited telomerase gene expression within 48 h of incubation in lymphoproliferative assays starting at a concentration of 0.27–6.75 µg/mL and accelerated telomere shortening in long-term cell culture experiments. Accelerated telomere shortening due to PCB exposure may lead to limitations of cell renewal and clonal expansion of lymphocyte populations. As PCB-related immune dysfunctions have been linked to increased susceptibility to infectious diseases and increased risk of cancer, our data provide a possible explanation, for how PCBs could promote infections and cancer through limiting immune surveillance.

In a German company polychlorinated biphenyls (PCB)-containing transformers and capacitors were recycled on a large scale. Human biomonitoring revealed a high PCB body burden in workers of the recycling company, in surrounding locations of this plant, in companies in the neighborhood of this plant, and in family members of these employees. In order to clarify whether possible adverse health effects occurred or may occur in the future, a prospective surveillance program was initiated. After an extensive literature search, an interdisciplinary group of experts developed a surveillance program based on current knowledge with respect to possible adverse health effects that might occur in the recycling process of transformers and capacitors. Exposure to various hazardous substances (PCB, polychlorinated dibenzo-p-dioxins and dibenzo-furans [PCDD/F], metals, solvents) was considered. Criteria derived from human biomonitoring results of PCB were used for admission to the program. Participants in the surveillance program are first informed about risks and aims of the program. Subsequently, physicians started a detailed documentation of participants' general and occupational history, with their complaints, diseases, and nutritional habits, as well as information regarding their living areas, by means of a standardized questionnaire. In addition, separate examinations were performed to detect possible neurological, immunological, (neuro)psychological, hormonal, and skin effects. Moreover, DNA exposure as assessed by the comet assay and antioxidative status were determined. The program will be offered at yearly intervals for 3 years, and then at 5 and 10 years after program onset. Until now the program has proved to be feasible, and acceptance among workers and their families has been high. Based on the results, criteria will be developed to define adverse health effects that might be attributable to a hazardous substance exposure.