Stephen B. Hamilton

Comparative Carcinogenicity in Sprague-Dawley Rats of the Polychlorinated Biphenyl Mixtures Aroclors 1016, 1242, 1254, and 1260

A comprehensive chronic toxicity and carcinogenicity study was conducted on a series of Aroclors (1016, 1242, 1254, and 1260). Each Aroclor was assessed at multiple dietary concentrations, ranging from 25 to 200 ppm, for 24 months in male and female Sprague-Dawley rats. Liver toxicity was indicated by elevated serum enzyme activity (AST, ALT, and GGT), elevated serum cholesterol concentration, decreases in hematologic parameters (RBC, Hb, and Hct), hepatocellular hypertrophy, an increased incidence of altered hepatocellular foci, and an increased incidence of hepatocellular neoplasms (primarily adenomas). Liver toxicity was distinctly more severe in females than in males. The incidence of hepatocellular neoplasms was highly sex-dependent (females >> males), differed between Aroclor mixtures and, for females, increased with dose and followed the general incidence pattern of Aroclor 1254 > Aroclor 1260 approximately Aroclor 1242 > Aroclor 1016. A significant response (p < 0.05) in males was seen only for the high dose of Aroclor 1260. A small increase in the incidence of thyroid gland follicular cell adenomas was noted in males for Aroclors 1242, 1254, and 1260, with the incidence being uniform across dose groups and Aroclor mixtures. For females, increased survival relative to controls was observed for all Aroclor treatment groups. A significantly decreased trend in the incidence of mammary gland neoplasms compared to control was also noted for females receiving Aroclors 1242, 1254, and 1260.

Levels of bioactive PCDF congeners in PCB dielectric fluids from capacitors and transformers

Abstract The levels of three pharmacologically active PCDF congeners, namely the 2,3,7,8,-tetra-, 2,3,4,7,8-penta-, and 1,2,3,7,8,9-hexachlorodibenzofurans, were measured by a precise two-dimensional gas chromatographic mass spectrometric procedure in PCB dielectric fluids taken from both used and unused capacitors and transformers, as well as in Aroclor standards. It was found that the electrical uses did not cause increases in bioactive PCDF levels.

PCB health effects

When Polychlorinated biphenyls (PCBs) were first introduced on the market as dielectric fluids, they were heralded as a major safety breakthrough. Fire safety codes demanded that PCB transformers and capacitors be used in major buildings. Some insurance companies would not write insurance on buildings that did not have PCB transformers.