ANALYSES OF CYTOGENETIC DAMAGE IN RODENTS FOLLOWING EXPOSURE TO SIMULATED GROUNDWATER CONTAMINATED WITH PESTICIDES AND A FERTILIZER

Male Fischer 344 rats and female B6C3F1 mice were each exposed through their drinking water to a mixture of pesticides and ammonium nitrate that simulated contaminated groundwater in California (California Chem ical Mixture [CCM]). Exposures were for 71 or 91 days, respectively. I n addition, B6C3F1 female mice were exposed for 91 days to another pes ticide and ammonium nitrate mixture (Iowa Chemical Mixture [ICM]) thro ugh their drinking water. The spleens were removed from the animals, a nd the splenocytes were cultured for analyses of sister-chromatid exch ange (SCE), chromosome aberrations (CA), and micronuclei (MN) in cytoc halasin B-induced binucleate cells. A concentration-related increase i n SCEs was found in the splenocytes of the rat at the 1 x , 10 x and 1 00 x levels of the CCM and at the 100 x concentration of the CCM in th e mouse. There were no other consistent cytogenetic effects observed w ith the CCM, and no statistically significant cytogenetic damage was o bserved in mice exposed to the ICM. Evidence from the literature is di scussed in order to infer which chemical or chemicals in the CCM might be responsible for the observed SCE response.