Polychlorinated biphenyls (PCBs): dermal absorption, systemic elimination, and dermal wash efficiency.

The objectives of this study were to determine the dermal absorption, systemic elimination, and dermal wash efficiency for polychlorinated biphenyls (PCBs). 14C-Labeled 42% PCB and 14C-labeled 54% PCB were topically and parenterally administered to rhesus monkeys and guinea pigs. Dermal absorption, determined by 14C urinary excretion, was extensive. In guinea pigs, 33% of the applied 14C-labeled 42% PCB dose and 56% of the 14C-labeled 54% PCB dose were absorbed. In rhesus monkeys, 15-34% of the labeled 42% PCB was dermally absorbed, depending on the magnitude of the applied dose. 14C-labeled 42% PCB applied to guinea pig skin was immediately washed with water and acetone. Only 59% of the applied dose was removed from the skin. A post-24-h washing removed only 1% of applied labeled 42% PCB and 20% of applied labeled 54% PCB. Postcontamination washing cannot be assumed to remove all contaminated PCB from skin. The body elimination of 14C was continuous and slow, with elimination half-lives on the order of 2-3 d in the guinea pig and 4-7 d in the monkey. Only 50-65% of an intramuscular dose could be accounted for in urine and feces for up to 28 d excretion. The elimination half-lives following topical administration were not much greater than that following intramuscular administration. This suggests that PCBs are rapidly and extensively absorbed through the skin, and that they are then probably generally distributed throughout the body, and then slowly eliminated.