Water Quality Criteria And Ecological Risk Assessment Of Copper In Chinese Freshwaters

The environmental pollution problem, especially heavy metal pollution, is always plagued us in recent decades. Copper due to its strong toxicity effect to aquatic organisms was selected as the research object in this study, and on basis of the backgrounds of biota characteristics and water quality condition in our country, the water quality criteria for aquatic life and ecological risk of copper in fresh water were scientifically investigated. Copper is a trace element in all living body, but excessive intake of the body will produce harmful effect, aquatic organisms tolerance of copper behaved much lower than that of mammals. In this study, we committed to make derivation of the freshwater biological water quality standard of China, meanwhile, the ecological risk status of dissolved copper in the main fresh water in China was analyzed. Acute and chronic toxicity tests were performed on selected representative native species as subjects, in combination with the toxicity data of other freshwater organisms collected, the water quality of copper was derived by the method of species sensitivity distribution. Finally, the ecological risk assessment of copper in freshwater was evaluated by using the method of quotient value, safety threshold and probability density overlap method.The results showed that the short-term risk concentration and long-term risk concentration of copper were 19.71μg·L-1 and 2.61μg·L-1, respectively, the results of risk analysis showed that the risk of the acute toxicity of copper to the water body of our country was lower relatively, however, in the case of long-term exposure to low doses, some waters will have a potential ecological risk to aquatic organisms. The water quality of copper obtained from present study was based on the derivation of the local species of toxicity experimental data, which with regional representation. In the experiment by using low-through method, the test result is more objective and accurate. The research results can provide data and theoretical support for the revision and risk assessment to water quality standard of copper in China.