Tetrachloroethylene: Balance and tissue distribution in male Sprague-Dawley rats by drinking-water administration

Abstract While low levels of organic contaminants have been reported to occur in drinking water, often little information is available concerning the toxicological significance of ingestion by this route. For tetrachloroethylene, considerable animal toxicity data exist for gavage or inhalation exposure. Since extrapolation of toxicity between routes of administration implies similar pharmacokinetic disposition, the pharmacokinetics of tetrachloroethylene was examined in rats following administration in the drinking water. Tetrachloro[ 14 C]ethylene was administered to adult, male Sprague-Dawley rats in saturated drinking water solutions (approximately 150 ppm) resulting in a mean dose of 8.1 ± 3.1 mg/kg. Within 72 hr from termination of a 12-hr drinking exposure period, approximately 88% of the body burden was eliminated as unmetabolized parent compound in expired air. As much as 96% of the activity recovered in this form was excreted during the first 24 hr. The remaining 14 C activity recovered was the result of metabolic conversion to 14 CO 2 (2.2%), nonvolatile metabolites in urine (7.2%) and feces (1.7%), and minor amounts (0.9%) in the carcass. Radioactivity in the carcass 72 hr following termination of the exposure period was distributed within liver, kidneys, fat, lungs, heart, and adrenals. Pulmonary elimination of unchanged tetrachloroethylene was monophasic with a calculated elimination half life of 7.1 hr. The elimination kinetics were consistent with results previously generated by both gavage and inhalation exposure. The fate of tetrachloroethylene following drinking-water administration was not substantially different from the disposition resulting from these two routes of administration.