title: Bioassay of lead dimethyldithiocarbamate for possible carcinogenicity.
abstract: A bioassay of technical-grade lead dimethyldithiocarbamate for possible carcinogenicity was conducted by administering the test chemical in feed to F344 (Fischer) rats and B6C3F1 mice. Groups of 50 rats of each sex and 50 mice of each sex were administered lead dimethyldithiocarbamate at one of two doses, either 25 or 50 ppm, for 104 or 105 weeks. Matched controls consisted of 20 untreated rats and 20 untreated mice of each sex. All surviving animals were killed at the end of the period of administration of the test chemical. Mean body weights of the dosed male rats and female mice were slightly lower than those of the corresponding controls; mean body weights of the dosed female rats and male mice were essentially the same as those of the corresponding controls. Survival rats in both species were unaffected by administration of the test chemical. The lack of toxicity in both species suggests that a maximum tolerated dose level may not have been used. Therefore, the studies may not have been conducted using maximum sensitivity for the assessment of the possible carcinogenicity of lead dimethyldithiocarbamate. No tumors occurred in the rats or mice of either sex at incidences that were significantly higher in the dosed groups than in the control groups. It is concluded that under the conditions of this bioassay, lead dimethyldithiocarbamate was not carcinogenic for F344 rats or B6C3F1 mice of either sex.