EVALUATION ON DIMINISHING EFFECTS OF DNA DAMAGING POTENTIAL BY HUMIC SUBSTANCES USING THE BACILLUS SUBTILIS REC-ASSAY

Abstract

Antimutagenic effect of humic substances has been reported by various investigators. In this research, the diminishing effect of DNA damaging toxicity by humic acid was evaluated for the influent and effluent of activated sludge tank receiving municipal wastewater and several DNA damaging chemicals {e. g., pyrene, 1-aminopyrene and benzo(a)pyrene} using Bacillus subtilis rec-assay. The diminishing effect was not apparent for influent but observed in the effluent. Among the DNA damaging chemicals, the DNA toxicity was effectively suppressed by humic acid for pyrene and benzo(a)pyrene. However, the effect was relatively smaller for 1-aminopyrene.