Mutagenicity of feeds and bovine milk in districts with different levels of environmental pollution.

Mutagenic activities of feedstuffs and bovine milk were investigated by the Ames test in two districts of the Czech Republic (Teplice and Prachatice), differing in the levels of industrial pollution. Salmonella typhimurium strains TA 98 and TA 100 with or without metabolic activation were used in the tests. Samples of currently fed feedstuffs and milk were collected in both districts in the spring 1992, autumn 1992, spring 1993, and autumn 1993. The Teplice and Prachatice sets included 12 and 11 representative samples, respectively. The samples were rinsed and extracted with acetone and methanol. Thus each sample was divided into four separate samples. The total number of revertants obtained in the industrial district Teplice was significantly higher than the corresponding value for the Prachatice district. Some between-the-seasons differences were also found within each of the two districts. The strain TA 98 proved to be more sensitive in the mutagenicity tests than the strain TA 100. Thirty-eight and thirty-one milk samples were collected in the districts Teplice and Prachatice, respectively. The overall evaluation demonstrated a significant between-the-districts difference in the total number of revertants induced by the milk samples in the strains TA 98 and TA 100.