Subchronic Toxicity of Ingested 1,3-Dichloropropene in Rats and Mice

Male and female Fischer 344 rats and B6C3F1 mice (10/sex/dosegroup) were given 0, 5, 15, 50, or 100 mg/kg/day (rats) or 0,15, 50, 100, or 175 (mice) mg/kg/day racemic 1,3-dichloropropene(1,3-D), respectively, via their diets for 13 weeks. Satellitegroups of rats (recovery = 10 rats/sex/group) ingesting 0 or100 mg/kg/day 1,3-D were provided control feed for an additional4 weeks to examine recovery. The test material was stabilizedin the feed by microencapsulation in a starch/sucrose matrix(80/20). The body weights of male and female rats Ingesting>5 and >15 mg/kg/day, respectively, and of all treatmentgroups of mice were decreased relative to controls. The terminalbody weights of high dose group rats and mice were decreasedapproximately 13–16%. A number of changes in serum biochemicalparameters and decreases in organ weights accompanied the depressedbody weights of these animals. Histologically, the only treatment-relatedchange observed was a slight degree of basal cell hyperplasiaand hyperkeratosis in the nonglandular portion of the stomachsof a majority of male and female rats ingesting >15 mg/kg/day.After the 4-week recovery period, most treatment-related changeswere noted to be reversible in nature. No treatment-relatedhistopathological changes were observed in the tissues of treatedmice. Based upon relatively slight depressions in body weightsat the lowest dosages tested, the no-observed-adverse-effectlevels for male rats and both sexes of mice were determinedto be 5 mg/kg/day and 15 mg/kg/day, respectively. A no-observed-effectlevel of 5 mg/kg/day was established for female rats.