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TISSUE CONCENTRATION OF PCBS IN ANIMAL EXPERIMENTS AS COMPARED WITH THOSE IN HUMANS WITH BACKGROUND-LEVEL EXPOSURE
Citation:
DeVito, M J. AND M. P. Longnecker. TISSUE CONCENTRATION OF PCBS IN ANIMAL EXPERIMENTS AS COMPARED WITH THOSE IN HUMANS WITH BACKGROUND-LEVEL EXPOSURE. Presented at SOT, San Francisco, CA, March 25-29, 2001.
Description:
TISSUE CONCENTRATION OF PCBS IN ANIMAL EXPERIMENTS AS COMPARED WITH THOSE IN HUMANS WITH BACKGROUND-LEVEL EXPOSURE. M J DeVito1 and M P Longnecker2. 1NHEERL, ORD, USEPA; Research Triangle Park, NC, USA; 2Epidemiology
Branch, NIEHS, Research Triangle Park, NC, USA.
To facilitate interpretation of experimental data on polychlorinated biphenyl (PCB) toxicity, we determined whether the PCB doses used in animal experiments result in tissue levels that were comparable to those observed in background-exposed humans. We identified 8 animal studies in which PCB tissue concentrations had been measured after oral dosing for more than one week, and compared the concentrations to those observed in 9 representative studies of background-exposed humans. Serum or whole blood concentrations of PCBs in the 9 human studies examined ranged from 0.8-19 ug/L. In animals exposed to PCB at doses > 1 mg/kg/d, blood concentrations of PCBs were, in general, at least 100 times greater than concentrations typically observed in background exposed humans. Several recent animal studies, however, have examined the effects of low-level PCBs (<0.05 mg/kg/d) in several species, with resulting tissue levels comparable to those in humans. Studies in dogs exposed to 0.01-0.03 mg/kg/d resulted in near maximal hepatic enzyme induction and blood concentrations within the range of background human exposures. Studies in primates exposed at 0.0075 mg/kg/d also resulted in blood concentrations within the range of background human exposures and were associated with developmental alterations. Such low-dose PCB studies demonstrating adverse effects in animals support the biologic plausibility that background-level PCB exposure in humans could have similar consequences. (This abstract does not reflect USEPA policy)