Preliminary aquatic life criteria development and ecological risk assessment of ammonia in seven major river basins in China

Abstract

Ammonia is one of the basin indices which are nation-controlled in the water environmental management. In order to assess the differences of ammonia criteria in different basins, 7 major basins are used for the study object, including Songhua River, Liaohe River, Haihe River, Yellow River, Huaihe River, Yangtze River and Zhujiang River, referring the water environmental criteria technology of the United States Environmental Protection Agency, based on the effects of water characteristics on the ecotoxicity of ammonia, and in summer and non-summer situation, aquatic life criteria is derived for ammonia. The results showed that: (a) 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 6 times, while those in different seasons in the same basin were greater than 2 times. (b) The summer acute and chronic criteria for Huaihe River were 0.37 mg/L and 0.06 mg/L while the non-summer values were 0.81 mg/L and 0.15 mg/L. Both the summer and the non-summer values were lowest in all of the seven basins. (c) The preliminary assessment of Ammonia exposure ecological risk indicated that was the lowest in Zhujiang River, and it was much lower in Songhua River, Liaohe River and Yangtze River, and was higher in Yellow River, and the highest in both Haihe River and Huaihe River. Haihe River has 7 sections while 2 in high risk, and Huaihe River has 27 sections while sixteen in high risk. According to the differences of the criteria values for ammonia in seven basins in different seasons and difference of ammonia ecological risk assessment, it is suggested that it should be managed by different policies.