Ecotoxicity evaluation of river water and sewage effluent using aquatic organisms and investigation of identification method for its causative toxic chemicals

随着科学技术的进步，各种化学物质得到了发展。释放到水环境中的低浓度化学物质会对水生生物造成潜在的环境污染。因此，评价含化学物质的废水对水生生物的影响，识别对水生生物具有毒性的致病物质具有重要意义。本研究利用固相萃取技术获取了释放到水环境中的化学物质的生态毒理学数据，并建立了生态毒理学实验系统。对河水和污水等实际环境样品进行了生态毒性评价，试图确定环境水样中存在的致病物质。从近年来被关注的水环境潜在环境污染物药物的生态毒理试验结果来看，抗生素对水生生物的毒性高于其他类型的药物。建立了与固相萃取技术相结合的生态毒理学实验系统，并将其应用于琵琶湖和益都河流域的水样中。污水和污水排放下游的河水样本显示出高毒性。对取自宜渡河流域的水样中对水生生物的毒性负责的致病化学物质进行了鉴定。高效液相色谱分离和生物测定相结合是鉴定致病物质的有效手段，分子量约为600的物质可能是造成生态毒性的致病物质之一。

Many kinds of chemical substances have been developed with the advancement of science and technology. The chemical substances with low level concentrations released into the aquatic environment would make potential environmental pollution on the aquatic organisms. Therefore, it is important to evaluate the impact by waste effluents containing the chemicals and identify causative chemicals which show toxicity on the aquatic organisms.In this research, acquisition of ecotoxicological data for chemical substances released into the aquatic environment and establishment of ecotoxicological experimental system using the solid phase extraction technique were conducted. Ecotoxicity of actual environmental samples such as river water and sewage effluent was evaluated and it was tried to identify the causative chemicals present in environmental water samples.From the results of ecotoxicological tests for pharmaceuticals, which are recently focused as potential environmental pollutants in the aquatic environment, antibiotics showed higher toxicity to aquatic organisms compared with that for other types of pharmaceuticals. Ecotoxicological experimental system combined with the solid phase extraction technique was established and applied to the water samples taken from Lake Biwa and Yodo River basin. High toxicity was shown for the samples of sewage effluents and river water downstream from the sewage effluent discharge. Identification of the causative chemical responsible for toxicity on aquatic organisms contained in water samples taken from Yodo River basin was conducted. Combination of fractionating using HPLC and bioassay was proved to be useful tool for identifying causative chemicals and the substance of about 600 of molecular weight is suggested to be one of causative chemicals for the ecotoxicity.