Development and verification of a toxicokinetic model of polychlorinated biphenyl elimination in persons working in a contaminated building

Abstract: Background: Polychlorinated biphenyls are toxic and slowly degrading substances that have been in widespread industrial use in the 1960s and 1970s. Despite a worldwide reduction, environmental exposure remains an issue; the assessment of an individual’s level of exposure at a given time in retrospect requires valid toxicokinetic modeling of the different PCB congeners. Objectives: To develop and verify a toxicokinetic model of the in vivo-degradation of PCB 28 and 52 in adult humans. Methods: The plasma concentrations of PCB congeners were measured in 583 persons working in a contaminated building for an average of 14.7±9.6 years. The values were adapted to a simple pharmacokinetic model (y t = y 0 ×(1−e−kt )); the steady state concentration y 0 was estimated based on the median values of persons working exposed more than 10 years. Results: The steady state concentration of PCB 28 was 0.10μg/l, that of PCB 52 0.02μg/l. The half-life of the congeners was estimated based on a logarithmic regression analysis according to the model mentioned above; it was 2.18 (95% CI: 1.91–2.54) years for PCB 28 and 3.95 (95% CI: 3.55–4.45) years for PCB 52, respectively. Stepwise elimination of persons with very long employment duration did not reduce the estimated half-life. Conclusions: The estimated half-life is higher than previously published data especially for PCB 52. Possible reasons and implications of this finding are discussed. [Copyright &y& Elsevier]