Study on pollution status of Microcystins in water bodies of water supply system of Chongqing City and the Three Gorges Reservoir

  Objective   To investigate the microcystin-LR(MC-LR)contamination status in the water bodies of water supply system of Chongqing City and the Three Gorges Reservoir.

  Methods   In May and August 2004, collecting water samples from five different water treatment plants and seven different sites of trunks and tributaries in the Three Gorges reservoir; taking intracellular and extracellular microcystins pretreatment and using high performance liqid chromatography (HPLC)with photodiode array to MC-LRconcentration detection.

  Results   (1) In five different water treatment plants, only had the intracellular microcytin-LRof HuaJi source water been detected, the concentration was 0111 μg/L.The other samples were not detected.(2)It was show n that MC-LRwas detected in water bodies of seven different collected sample sites of the Three Gorges reser voir in plentiful phase, August 2004.The total concentrations of MC-LRin source waters varied from 0.07 to 0.57 μg/L.The detectable percentages of MC-LRin extracellular and intracellular pretreatment samples were 86% and 43% respectively.

  Conclusion   The MC-LR concentration of detected samples did not exceed the guideline value for MC-LRtoxicity equivalents of 1 μg/Lin dr inking water set by WHO.(1)No MC-LRwas detected in the final water samples of five water treatment plants in municipal water suply, the drinking water of Chongqing city is safe product.(2)The microcystin contamination level is very low in water bodies of the Three Gorges reser voir.