Distribution and elimination of hexachlorocyclopentadiene in rats and mice.

14C-Hexachlorocyclopentadiene (HEX, C56 ) was administered to adult rats and mice as a single oral dose (2.5 and 25 mg/kg) and as a component of the diet (1, 5 and 25 ppm) for a maximum of 30 days. The primary route of excretion was via the feces (-70% of dose) with low elimination in the urine (approximately 15%). Biliary excretion of only 16% with 66% still voided in the feces of bile duct cannulated rats suggested that the majority of orally consumed HEX was not absorbed. However, extensive degradation apparently occurred in the gut since little of the fecal material was of an apolar nature. The kidney, liver, ovaries and fat were the major sites of deposition of 14C-HEX equivalents. In rats, the kidney contained the highest levels of residues, whereas in mice the residues in the liver exceeded those in the kidney. Other than this difference, the fate of HEX in rats and mice, both male and female, was quite similar and in each case the tissue residues reached a plateau after about two weeks on the HEX-containing diets.