Tissue residues from subacute oral feeding of polychlorinated biphenyl dielectric fluids

The results of this study can be summarized as follows: (1) Monochlorobiphenyl and the 30%-chlorinated biphenyl MCS 1043 did not accumulate in the lipid reservoir of the rats when fed at 25 ppm and 100 ppm in the diet. This result indicates that mono-, di-, and trichlorobiphenyls are readily metabolized and/or excreted under the conditions of this study. (2) Although a fraction of the ingested Aroclor 1242 and Aroclor 1016 was stored in the rats' lipid reservoir, most of this residue was depleted after the rats had been on the basal laboratory diet for several weeks. (3) Residues of Aroclor 1016 accumulated more slowly and to a significantly lesser extent than those of Aroclor 1242. During the recovery period these PCB residues decreased to lower values for Aroclor 1016. This result indicates that a product containing reduced amounts of the more highly chlorinated PCBs should have improved environmental compatibility.