加氯消毒对水中有机提取物致人胎肝细胞DNA损伤的影响

DNA Damage in L-02 Cells Exposed to Organic Extracts of Chlorinated Drinking Water

目的探讨自来水加氯消毒对水中有机提取物致细胞DNA损伤的影响。方法于2007年7月(夏季)和2008年3月(春季)采集以长江为水源的某水厂的水源水、经加氯消毒处理后的出厂水和末梢水,以人胎肝细胞(L-02)为靶细胞,采用单细胞凝胶电泳技术,检测水样有机提取物诱导细胞DNA损伤的效应。水样有机提取物设4个染毒浓度(1.2、6、30、150ml/ml),阳性对照为苯并(a)芘(200μmol/L),溶剂对照为二甲基亚砜(DMSO,10μl/ml)。结果春季水源水、出厂水和末梢水以及夏季出厂水和末梢水水样有机提取物在低、中、高浓度(6、30、150ml/ml)引起的L-02细胞DNA损伤较溶剂对照组明显增加。春夏两季加氯消毒后的出厂水和末梢水有机提取物在低、中、高浓度(6、30、150ml/ml)引起的L-02细胞DNA损伤较水源水明显增强。春季的水样有机提取物对细胞DNA的损伤作用高于夏季。结论水源水、出厂水和末梢水有机提取物均能引起L-02细胞的DNA损伤,氯化消毒增加了水源水的遗传毒性,春季水样的遗传毒性大于夏季。

Objective To investigate the effect of chlorination disinfection of drinking water on DNA damage induced by organic extracts of water. Methods Water samples including raw water,finished water after chlorination disinfection and tap water were collected in a water plant near Yangtze River of Wuhan in spring （March, 2008） and summer （July, 2007）, respectively. The DNA damage induced by organic extracts of water samples were detected with single cell gel electrophoresis （SCGE）. Human embryonic liver cell line （L-02） was exposed to the organic extracts of water samples at the doses of 1.2,6,30 and 150 ml water/ml medium. DMSO （10 μl/ml） and B（a）P （200 μmol/L） were used as the negative control and positive control,respectively. Results Compared with the negative control, organic extracts from raw water in spring, finished water after chlorination disinfection and tap water in the two seasons led to a significant increase of DNA damage in L-02 cells at the concentrations of 6,30,150 ml/ml medium. In comparison with the raw water samples, a significant increase of DNA damage was caused by samples of finished water after chlorination disinfection and tap water collected in the two seasons. DNA damage caused by organic extracts of water samples in spring was higher than that in summer. Conclusion Organic extracts from raw water,finished water after chlorination isinfection and tap water can induce DNA damage in L-02 cell. Chlorination disinfection may enhance the genotoxicity of raw water. The water samples collected in spring may present higher genotoxicity compared with the summer samples.