水源水中微囊藻毒素的遗传毒性与健康风险评价

Assessment on genotoxicity and health risks of microcystin in drinking water sources

应用美国EPA健康风险评价模型对浙江省101个饮用水源地微囊藻毒素(MC)的健康风险度进行评价,提示水源水中微囊藻毒素-LR(MC-LR)具有较高的非致癌风险.采集MC污染相对严重的A、B2饮用水源,一部分利用树脂对其中的MC进行浓集,另一部分加入稀释的纯毒素MC-LR模拟水源水中MC释放的情况,同时制备相同浓度的纯毒素序列,利用Ames试验检测藻毒素浓集物、水样中藻毒素和纯毒素对细菌的致突变性,彗星试验检测人外周血淋巴细胞可能产生的DNA损伤,微核试验检测鲤鱼红细胞微核的诱发效应.结果表明,与阴性对照组相比,藻毒素浓集物、纯毒素和藻毒素稀释水样均可引起人外周血淋巴细胞DNA的不同程度损伤(P<0.01),损伤随着染毒剂量的增加而加重,高剂量浓集物、藻毒素稀释水样A和纯毒素可诱导鲤鱼红细胞微核率上升,在本实验条件下尚未观察到藻毒素浓集物、藻毒素稀释水样及纯毒素在Ames试验中具有显著的致突变作用.利用树脂浓集水源水中MC和向水源水中加入稀释的MC-LR模拟MC释放2种方法切实可行,饮用水源水中MC可诱导鲤鱼红细胞微核率上升和淋巴细胞DNA损伤,具有遗传毒性,可能对人体健康产生的远期危害.

To assess the genotoxicity of microcystin （MC） in drinking water source for bacteria,carp and human,high health risk of MC-LR was observed,based on concentrations of organic pollutants in 101 drinking water sources of Zhejiang province. Surface water of 2 typical drinking water source A and B were sampled,which were relatively seriously polluted by MC-LR. The diluted microcystin of MC-LR was added to the water samples,while MC-LR-containing purified water was prepared. The HLB resin was used to absorb and concentrate the microcystin in source water samples. The bacteria,human peripheral blood lymphocytes and ornamental carp erythrocyte were treated by purified water,drinking water source A and B,concentrated water samples,and MC-LR-containing purified water,respectively. The mutation of bacterial DNA was assessed by Ames test. The DNA damage of human peripheral blood lymphocytes was tested by comet assay. Micronucleus of ornamental carp erythrocyte was measured by micronucleus test. Compared with purified water,drinking water source A and B,concentrated samples,and MC-LR-containing purified water resulted in DNA damage of human peripheral blood lymphocytes （P0.01）. With the concentration of MC-LR increasing,the level of DNA damage was growing up. Likewise,concentrated water samples and MC-LR-containing purified water were able to induce higher frequency of micronucleus in carp erythrocyte. However,DNA mutation induced by concentrated water samples,drinking water source A and B,and MC-LR-containing purified water were not observed. It is practical to simulate the microcystin-releasing with MC-LR dissolving in drinking water source. Microcystin in drinking water source could induce micronucleus in carp erythrocyte and DNA damage in human lymphocytes. It indicated that MC-LR may have the potential adverse effects on human health.