Study On Contamination Level Of Microcystin In Surface Waters Of The KunShan Area And Its Toxic Effects

This paper investigates the season variation of algae and its microcystin in sueface waters of the KunShan area. The adverse effects of MCLR on the liver and lymphocyte of mice and human beings were studied by the biochemical assay and the single cell gel electrophoresis technique. The purpose of the study is to provide guides of information in improving the water quality in this area.Results of the study indicated: (1) The types and concentrations of algae in waters varied in different months of a year, hi February, the algae concentration is the lowest, and the Bacillariophyta and the Chlorophyta were dominant types. In August, the situation was contrary with the Cyanophyta being dominant. (2) The MCLR concentration in raw and tap water changed in different seasons. The highest level was found in August, but not detectable in February. A correlative relationship existed between the average level of MCLR and the chemical oxygen demands, the ratio of nitrogen/phosphorous and temperature. (3) Health effects of MCs in human drinking water were surveyed. The levels of hepatic enzyme AKP of the males were apparently higher than that of the females (p<0.05). The adverse effects of MCLR on human lymphocyte were revealed. (4) At the concentration of lug/L, MCLR could increase the levels of AST and LDH, and the migrating rate of the lymphocyte DNA; at the concentration of 1000ug/L, MCLR could enhance the rate of lymphocyte micronuclear compaired with the control group and the lug/L group.Results of the study suggest that there is a obvious eutrophication in surface waters of the KunShan area; the growth of algae and the levels of MCLR represent seasonal changes; at the concentration of lug/L, MCLR canbring about adverse effects on the liver and lymphocyte. Therefore, the present MCLR standard of lug/L in drinking water posed by WHO is probably not safe enough in protection of the resident health in this area.