Derivation of a health based guidance value for PCS in human blood samples

摘要

Polychlorinated Biphenyls (PCB) are persistent synthetic organochlorines. Due to their lipophilicity they accumulate in the food chain and in human lipid tissue, and can cause a variety of dose-dependent adverse health effects in different tissues and organs. Although their prohibition in the early 1980ies led to a significant decrease of the body burden of the population, PCBs are still widespread due to their high persistency in the environment and may still be emitted, e. g. in case of improper recycling. A critical literature review was carried out, to weight the evidence of the current state of research on health effects of PCB, under special consideration of publications from the recent years. Based on this review the critical toxic endpoints were identified; key studies on the dose response relationship based on human data were selected, and critical effect levels in human blood were derived. The risk assessment was based on neurotoxic and immunotoxic PCB-effects as most sensible critical endpoints. Both have been largely investigated epidemiologically, mostly in birth cohorts, from which age-dependent neurodevelopmental deficits were reported for newborns and infants. Also elevated incidences of infections, lower allergy rates, suppressed immune responses on vaccinations, and shifts in certain lymphocyte-subpopulations were associated with the pre- and postnatal PCB exposition in several cohort studies. Data from animal studies supports the epidemiological findings. Therefore children were identified as the most vulnerable group. The overall result of the risk assessment showed that below concentrations of 0.5 μg total PCB / g blood lipid no adverse health effects may occur. Based on this risk assessment the German "Human Biomonitoring Commission" derived the following HBM values for total PCB: HBM-I = 3.5 μg PCB/L serum; HBM-Ⅱ = 7 μg PCB/L serum for children and women at childbearing age.