Evaluation of genotoixic potency on substances contained in night soil and its reduction performance by ozonation

摘要

Bacterial assay which can detect the induction of error-prone repair genes on the DNA was applied to the samples which were cellected at a night soil treatment plant. The genotoxicity on each smaples was measured by using this bacterial assay, called umu test. The strong genotoxic potency was found in the sediments of the raw night soil, that ism human feces. There are some substances which shows the toxicity on the DNA and are attributable to the baked foods or metabolites in the human digestive organs. These potencies could not be easily removed in the biological decomposition process through the survey of the treatment plant. It was quite clear that more effective reduction by ozonation with about 1 mgO_3/mgC could be achieved.