Mutagenic activity of swimming-pool water.

Swimming pool water, being chlorinated and exposed to trace organics from use was investigated as a possible source of mutagens using the Salmonella/mammalian-microsome test. Procedures previously described for the extraction of trace organics from water using XAD-2 macroreticular resin were modified to allow quantitative extraction of mutagens. These procedures were superior to freeze-drying and solvent-extraction. Using a base-pair histidine mutant, strain TA100, of Salmonella typhimurium significantly mutagenic responses were observed using concentrates from 3 variations of the extraction procedure. Acidified pool-water extracts eluted with ether or acetone were mutagenic, the former enhanced in the presence of the induced microsomal fraction from rat livers. Non-acidified pool-water extracts eluted with acetone were mutagenic without microsomal activation. These results indicate the presence of more than one mutagen in what is likely a complex mixture of organic molecules in swimming-pool water.