Mutagenic potential of runoff water from soils amended with three hazardous industrial wastes

Abstract

The bacterial mutagenicity of runoff water from soils contaminated with hazardous industrial waste was monitored for a three-year period using Salmonella typhimurium strain TA98 with and without metabolic activation. The wastes included a wood-preserving waste, a combined American Petroleum Institute (API) separator/slop oil emulsion sludge and a storm-water runoff impoundment waste. The wastes were applied to a Weswood silt loam soil (Fluventic Ustochrept) and a Bastrop clay loam soil (Udic Paleustalf) at a rate of 3.1% (wt./wt.) for the wood-preserving waste and of 4.5% for the two refinery wastes. The results indicate that the runoff water from each of the waste-amended soils contained mutagenic constituents. The maximum specific activity was 783 net revertants per milligram residue, which was induced by the runoff water collected from the storm-water runoff impoundment-amended Weswood soil 360 d after application and assayed with metabolic activation. This sample also yielded the maximum weighted activity of 6,554 revertants per liter of runoff water. The mutagenic activities of the runoff water from all waste-amended soils displayed significant increases through 360 d after application and, in most cases, significant decreases in the samples collected approximately three years after application. The mutagenic activities of the runoff water from the Weswood soil were consistently greater than the activities of the runoff water from the Bastrop soil. These results indicate that three years or more may be required for the mutagenic activity of runoff water to return to background level, and that different soils will differ in their capacities to retain mutagenic chemicals during rainfall events.