Mutagenic activity of runoff and leachate water from hazardous waste land treatment

Abstract

The mutagenic potential of runoff and leachate water from petroleum sludge-amended soils was determined using the Salmonella microsome assay and the Bacillus subtilis DNA repair assay. The runoff and leachate samples were collected from four different soils amended with an API-separator sludge from either a petroleum refinery or a petrochemical plant. While mutagenic activity was detected in a limited number of runoff and leachate samples, greater amounts of mutagenic activity were detected in the runoff water. The majority of samples which were toxic to Salmonella at low dose levels induced increased lethal damage to DNA repair-deficient strains of B. subtilis. Generally, the mutagenic activity of leachate water and the runoff water from two of the three soils decreased with time following waste application. The activity in the third soil did not decrease over the 3 years of observation. The amounts of activity released from the soil in the leachate and runoff water were small compared with other environmental exposures, indicating that while land treatment may allow some release to the environment, the impact is likely to be small. The results also indicate that microbial bioassays may prove to be a useful tool for environmental monitoring of land treatment facilities.