两种含氯消毒副产物对草履虫急性毒性效应初探

Abstract

氯化消毒是我国普遍采用的城市污水消毒措施，然而，氯化消毒的同时，氯与水中的有机物发生反应生成一系列的卤代烃类化合物，即氯化消毒副产物。经研究证实大部分氯化消毒副产物具有致癌、致突变、生殖毒性效应。为研究消毒废水中一些副产物的毒性，本研究采用消毒废水中的有害副产物三氯甲烷(CHCl3)和三溴甲烷(CHBr3)为毒物材料，以草履虫为受试生物，对其种群进行单一急性毒性和联合毒性实验，探究CHCl3和CHBr3对草履虫的急性毒性和联合毒性。实验结果表明，两种毒物单独作用时，随着浓度增大，毒性作用也增大，CHCl3的1 h半致死浓度(LC50)为1585.27 μg/L，CHBr3的1 h半致死浓度(LC50)为656.37 μg/L，两种毒物共同作用时表现为协同作用。由于草履虫对两种毒物毒性较为敏感，其可作为CHCl3和CHBr3的毒性评价生物。 Chlorination is widely applied to disinfect drinking water in China. However, a series of chlori-nated disinfection by-products (CDBPs) are formed when chlorine reacts with organic matters in water health. Many CDBPs can cause health hazards for human, for example, cancers and mutagenic and reproductive toxicity. For the study of disinfection by-products in some wastewater toxicity, this study used the harmful by-products, chloroform (CHCl3) and methyl bromide (CHBr3) in disinfection wastewater, as poison materials. In single acute toxicity test and joint toxicity test, the acute toxicity and joint toxicity of CHCl3 and CHBr3 to paramecium were studied. The results show that, when the two toxicants work separately, toxic effects increase along with the increasing concentration. The median lethal concentration (LC50) of CHCl3 in 1 h was 1585.27 μg/L and that of CHBr3 was 656.37 μg/L, and it showed a synergistic effect when combining two poisons. Since paramecium is sensitive to the toxicity of the two poisons, it can be used to evaluate the toxicity of CHCl3 and CHBr3.