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，许多化学物质被开发出来。低浓度的化学物质释放到水环境中会对水生生物造成潜在的环境污染。因此，评价含化学物质废水对水生生物的影响，确定对水生生物具有毒性的化学物质具有重要意义。本研究采用固相萃取技术，采集了废水中化学物质的生态毒理学数据，建立了废水中化学物质的生态毒理学实验系统。对河水、污水等实际环境样品进行了生态毒性评价，试图找出环境水样中存在的致病化学物质。从最近被关注为水环境潜在环境污染物的药物的生态毒理学测试结果来看，抗生素对水生生物的毒性比其他类型的药物更高。建立了固相萃取技术结合生态毒理学实验系统，并应用于日本琵琶湖和淀川流域的水样。污水排放物和污水排放物下游的河水样品显示出高毒性。对淀川流域水样中导致水生生物毒性的化学物质进行了鉴定。HPLC分离与生物测定相结合是鉴定致毒物质的有效手段，分子量约为600的物质可能是引起生态毒性的致毒物质之一。

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.