Ra Jin Sung, Kim Sang Don, Chang Nam Ik, An Kwang-Guk
Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, South Korea.
Environ Toxicol Chem. 2007 Sep;26(9):2010-8. doi: 10.1897/06-542R.1.
Whole effluent toxicity (WET) tests and ecosystem health assessments, based on test guidelines of U.S. Environmental Protection Agency (U.S. EPA) and index of biological integrity (IBI), were conducted on various streams located in Youngsan River watershed, Korea. The WET tests showed that about 33 and 82% of wastewater treatment plants (WWTPs) exhibited significant toxicity to Daphnia magna and Selenastrum capricornutum, respectively. Small WWTPs with low discharge volumes contributed less than 1% to the total stream toxicity. Fish community compositions and trophic guild analysis showed that the diversity index was greater in the control than in impacted streams, and the proportion of omnivore species was less in the control. Also, ecosystem health assessments, based on the IBI, showed distinct differences between the control and impacted sites of WWTPs. Model values of the IBI, based on 12 stream data sets, averaged 28, which is judged as a fair to poor condition according to the U.S. EPA criteria. The mean IBI in the control sites was 42, indicating good stream condition, whereas the impacted sites was scored 21, indicating poor condition. Overall, WET tests and ecosystem health assessments suggested the WWTP effluents had evident toxic effects on the biota, and impacted the species compositions and trophic guilds, resulting in degradation of the stream ecosystem health.
依据美国环境保护局（U.S. EPA）的测试指南以及生物完整性指数（IBI），对韩国荣山江流域的各条溪流开展了全废水毒性（WET）测试和生态系统健康评估。WET测试表明，分别约有33%和82%的污水处理厂（WWTPs）对大型溞和羊角月牙藻表现出显著毒性。低排放量的小型污水处理厂对溪流总毒性的贡献率低于1%。鱼类群落组成和营养类群分析表明，对照溪流中的多样性指数高于受影响溪流，杂食性物种在对照溪流中的比例更低。此外，基于IBI的生态系统健康评估显示，污水处理厂的对照站点和受影响站点之间存在明显差异。基于12个溪流数据集的IBI模型值平均为28，根据美国环境保护局的标准，这被判定为状况一般至较差。对照站点的IBI均值为42，表明溪流状况良好，而受影响站点的得分为21，表明状况较差。总体而言，WET测试和生态系统健康评估表明，污水处理厂的废水对生物群具有明显的毒性作用，影响了物种组成和营养类群，导致溪流生态系统健康状况恶化。
