Slight Maternal Toxicity Research Articles

Chronic Toxicity and Reproduction Studies of Hexachlorobutadiene in Rats

Hexachlorobutadiene (HCBD), while not produced commercially in the United States, may be encountered as an unwanted by-product of certain processes associated with the chlorination of hydrocarbons. Studies were conducted to assess the potential long-term toxicity of HCBD. In a reproduction study conducted in rats, dose levels of 20 or 2.0 mg/kg-day of HCBD induced slight maternal toxicity (primarily of the kidney) but caused no adverse effects on reproductive parameters—percent pregnancy and neonatal survival/development. A decreased neonatal body weight was noted at the highest dose level of 20 mg/kg-day of HCBD. No toxicologic effects were observed among the adults at a dose level of 0.2 mg/kg-day or among the neonates at dose levels of 0.2 or 2.0 mg/kg-day of HCBD. In a chronic toxicity study in rats, ingestion of 20 mg/kg-day for up to 2 years caused multiple toxicologic effects, primarily of the kidney, including the development of renal tubular adenomas and adenocarcinomas. Ingestion of the intermediate dose level of 2 mg/kg-day caused lesser degrees of toxicity, but no evidence of neoplasia. Ingestion of the lowest dose level of 0.2 mg/kg-day of HCBD caused no effects that could be attributed to treatment. These data indicate a dose-response relationship for HCBD-induced toxicity affecting primarily the kidney. HCBD-induced neoplasms occurred only at a dose level higher than that causing discernible renal injury.