Abstract
The correlation of the mutagenicity of tap water with its raw water quality was studied in summer and winter using Salmonella typhimurium TA98 and TA100, in order to understand the difference in mutagenicity of municipal tap water from two different water supply systems. As a result, the mutagenic activity, TNVOX, MX and KMnO4 consumption in tap water from the river water-line water supply system were higher than those from the lake water-line water supply system. The mutagenic activity of tap water from the river waterline water supply system was found to have a positive correlation with the TOC of its raw water. It was considered that existence of some precursors of by-products became mutagenic after chlorination and that mutagenic substances existed in river water. The mutagenic activity of municipal tap water from the lake waterline water supply system was highly negatively correlated with the volume of water reservoir. It was assumed that the markedly high mutagenicity was caused by the decrease in water volume in the reservoir owing to a drought. The ratio of the mutagenic activity of tap water per KMnO4 consumption of raw water in winter was significantly higher than that obtained from the study of municipal tap water samples in summer.
