Chronic Toxicity and Three-Generation Reproduction Study of Styrene Monomer in the Drinking Water of Rats

Chronic Toxicity and Three-Generation Reproduction Study ofStyrene Monomer in the Drinking Water of Rats. BELILES, R. P.,BUTALA, J. H., STACK, C. R., AND MAKRIS, S. (1985). Fundam.Appl. Toxicol.. 5,855-868. Chronic toxicity and reproductiveperformance were evaluated in groups of rats receiving styrenemonomer in their drinking water at nominal concentrations of0, 125, or 250 ppm. Fifty male and 70 female rats in each testgroup and 76 males and 104 females in the control group wereplaced on a 2-year study and followed for observations of generalhealth which included measurement of body weight, food and waterconsumption, hemograms, clinical chemistries, urinalysis, andhistopathological examination. Ten males and 20 females fromeach group in the study were mated to produce F₁ pups. Thesepups were subsequently mated to produce three generations ofoffspring, all maintained on styrene-treated drinking water.For each generation, the following were evaluated: fertility,litter size, pup viability, pup survival, sex ratio, pup bodyweight, weanling liver and kidney weight, and marrow cytogenetics.Except for a statistically significant reduction in water consumptionfor styrene-treated rats, no treatment-related changes, includingmortality patterns, were reported for animals in the chronicstudy. The data evaluated for reproductive performance alsoshowed no evidence of styrene-related changes. It was concludedthat the administration of styrene in the drinking water ofrats for 2 years produced no deleterious dose-related effectsor decrements in reproductive performance.