Urinary mutagens in municipal sewage workers and water treatment workers.

In view of the potential exposure of sewage treatment workers to a multitude of mutagenic substances, the frequency of urinary mutagens was measured by the Ames test among a sample of 164 sewage treatment workers employed in 14 sewage treatment plants which processed between 3 and 10 million gallons of sewage daily in New York State between March and July, 1984. The frequency was compared to that observed in 72 water treatment employees in the same municipalities. Sewage workers had a significantly higher risk for urinary mutagens after controlling for smoking, using the Ames test, both with and without the addition of the liver microsomal homogenate, S-9. More precise methods of measuring exposure in epidemiologic studies, particularly in environmental and occupational epidemiology, are in various stages of development. The application of one of these methods, the Ames test, to an occupational group (sewage workers) with potentially high exposure to mutagenic substances is described and the strengths and limitations of this application are discussed.