七大流域氨氮水生生物水质基准与生态风险评估初探

氨氮是我国流域水环境管理的国控指标之一,为评估不同流域的氨氮基准差异性,以七大流域(松花江流域、辽河流域、海河流域、黄河流域、淮河流域、长江流域和珠江流域)为研究对象,基于水质参数对氨氮毒性的影响,借鉴US EPA(美国国家环境保护局)水环境基准技术方法,分夏季和非夏季2种情况推算了各流域氨氮水生生物基准值. 结果显示:①流域和季节的不同导致氨氮基准值的差异均很明显,不同流域的氨氮基准值差异可超过6倍,同一流域不同季节的氨氮基准值差异可超过2倍. ②淮河流域夏季和非夏季氨氮基准值均为最低,夏季氨氮急、慢性基准值分别为0.37和0.06 mg/L,非夏季分别为0.81和0.15 mg/L. ③氨氮暴露生态风险初步评估结果表明,珠江流域风险较小；松花江流域、辽河流域、长江流域次之；黄河流域风险较大；海河流域和淮河流域风险最大,海河7个断面中有2个存在高风险,淮河27个断面中16个存在高风险. 根据各流域不同季节氨氮基准值及氨氮暴露生态风险的差异,建议对不同流域、不同季节实行差异化管理. 

Preliminary Aquatic Life Criteria Development and Ecological Risk Assessment of Ammonia in Seven Major Basins in China

Abstract: Ammonia is one of the nationally-controlled indexes in ambient water environmental management. In order to assess the difference of ammonia criteria in different basins, seven major basins were used as the study object:Songhua River, Liaohe River, Haihe River, Yellow River, Huaihe River, Yangtze River and Zhujiang River. The water environmental criteria of the United States Environmental Protection Agency, based on the effects of water characteristics on the ecotoxicity of ammonia, were used to derive aquatic life criteria for ammonia in summer and non-summer. The results showed that:1) the differences between the criteria values in different basins and different seasons were significant. The differences between the criteria values in different basins were greater than six times, while that in different seasons in the same basin were greater than two times. 2) The summer acute and chronic criteria for Huaihe River were 0.37 and 0.06 mg/L, while the non-summer values were 0.81 and 0.15 mg/L, respectively. Both the summer and the non-summer values were lowest in all of the seven basins. 3) The results of ecological risk showed that the risk was low in Zhujiang River, and was moderate in Songhua River, Liaohe River and Yangtze River, and was higher in the Yellow River, and the highest risk occurred in Haihe River and Huaihe River. Haihe River has seven sections, including two at high risk, and Huaihe River has twenty-seven sections, including sixteen at high risk. This suggested that according to the differences of the criteria values for ammonia in the seven basins under different seasons, and differences of ammonia ecological risk assessment, it should be managed according to different policies.