||O'Brien and Gere Engineers, Inc., Syracuse, NY. ;Onondaga County Dept. of Drainage and Sanitation, North Syracuse, NY.;Municipal Environmental Research Lab., Cincinnati, OH.
The introduction of potential mutagens to the human environment may serve to increase the rate of contact with substances that contribute to cancer incidence in the general population. The primary purpose of this study was to evaluate combined sewer overflows and urban runoff for the presence of chemical mutagens. The Ames Salmonella/microsome mutagenicity test was employed as a general biological effects test for the qualitative detection of mutagens in the sanitary environment, including rain, urban runoff, sanitary wastewater, combined sewer overflows, sewage treatment plant effluent, and receiving waters. The Ames test is a relatively sensitive and simple bacterial test for detecting chemical mutagens. Its advantages over long-term animal tests are speed, ease, and relative low cost. The test employs previously mutated Salmonella typhimurium LT2 bacterial strains which have a tendency to undergo a subsequent mutation back to their natural state when exposed to mutagenic compounds. Nineteen samples elicited a detectable response to one or more of the five Salmonella typhimurium test strains, with or without metabolic activation. Nine of these samples (47%) were of urban runoff in the project area, metropolitan Syracuse (Onondaga County) N.Y., including 17 of 30 detectable responses (57%). Five of the samples (26%) were from combined sewer overflows (7 of 30 detectable responses, or 23%).