Water Quality Criteria And Ecological Risk Assessment Of Copper In Langcang River

The criteria of water quality is basis on water quality standards development and environmental management, which can scientifically reflect of pollutants for the ecological effects. Ecological risk assessment (ERA) is the method for assessing the risk foundation of ecosystem under toxic effects and exposure feature of contaminants, and provides theoretical support for environmental risk management decision-making. At present, water quality standards in China were established mainly according to the foreign water quality criteria or water quality standards, which can not guarantee the safety of aquatic ecosystems and human health in China. First determine sampling plots based water quality monitoring datas, and test some water quality parametes and analyze spatial and temporal characteristics of Lancang River water quality. Then copper acute toxicity to fish was done under different DOM concentration in artificial water. Lastly, this research built water quality criteria system of Lancang River in combination with biota features in Lancang River for protecting the freshwater aquatic organisms based on the summarizations of the water quality criteria systems from different countries. The copper toxicology database of Lancang River species was established and standardized using the Biotic Ligand Model(BLM) on the basis of literature researching, species selection, quality screening process,. Then, the reference value of copper, and assess ecological risk for copper content of the Lancang River were derived using the species sensitive distribution method. The study may have important reference for relative water quality criteria and standard in China.The main conclusions of this study as following:1. The experiment result of the copper acute toxicity to fish in different DOM concentrations showed that the copper acute toxicity to fish was decreasing with the increasing of DOM concentration.2. The acute reference value of upstream, midstream, downstream in Lancang River were22.39μg/L,31.20μg/L,26.79μg/L, respectively, which were higher than other country’s. The chronic reference value was1.11μg/L, which is lower than other country’s. All of these values were lower than the surface water environmental quality standards in China. Therefore, the surface water quality standards can not protect the Lancang River aquatic organisms, which can cause the question of "less protection". So it is suggested that the water quality standards of Lancang River should be improved.3. The potential risks of the copper on the upstream, midstream, downstream in Lancang River were6.48%,4.15%,0.05%, respectively. These results indicated that the effect of copper pollution in the surface water of Lancang River is low adverse.