我国氨氮海水质量基准的探讨

Development of seawater aquatic life criteria for ammonia in China

我国现行的氨氮海水质量标准参照国外基准与标准制定,未考虑是否能够有效保护中国海洋物种,科学性欠缺。对我国海水氨氮质量基准进行研究,采用美国EPA推荐的物种敏感度排序（SSR）技术,结合美国海水氨氮水质基准数学模型,搜集利用我国15种海水水生生物的非离子氨毒性数据,根据非离子氨氮和总氨氮转换公式,得出水体在不同pH值、温度和盐度条件下的总氨氮水质基准在pH为7.09.0、温度为030℃的范围内,盐度为10时,基准最大浓度（CMC）和基准连续浓度（CCC）的范围分别为0.08957.141mg/L与0.0074.365mg/L;盐度为20时,CMC和CCC的范围分别为0.09261.152mg/L与0.0074.671mg/L;盐度为30时,CMC和CCC的范围分别为0.09565.446mg/L与0.0074.999mg/L;3个环境因子,对CCC和CMC的影响程度由大到小依次为：pH、温度、盐度。相对于美国,我国急性基准的取值区间收缩了5倍,慢性基准的取值区间收缩了10倍。研究结果认为,现行的非离子氨数值应修正为0.007mg/L才能有效保护我国海洋生物,同时建议使用总氨氮的基准来管理海水中氨氮变化。为修订我国氨氮海水质量标准提供了科学依据。

The current quality standard of ammonia in seawater in China was made based on the foreign water quality criteria and standard,yet it lacked the support of scientific data to verify whether it could effectively protect the resident species in seawater.Study on the seawater aquatic life criteria for ammonia in China mainly applied the species sensitivity rank（SSR）and the mathematic models developed by the United States Environmental Protection Agency（US EPA）in making their ammonia criteria in seawater.The total ammonia criteria were derived by a formula conversion from non-ionized ammonia criteria using toxicity data of 15 seawater species in China.When pH ranges from 7.0to 9.0,and temperatures from 0℃to 30℃,as salinity is 10,criteria maximum concentration（CMC）and criteria continuous concentration（CCC）of the total ammonia ranges from（0.089-57.141）mg/L and（0.007-4.365）mg/L,respectively;as salinity is 20,CMCand CCCranges from（0.092-61.152）mg/L and（0.007-4.671）mg/L respectively;as salinity is 30,CMCand CCCranges from（0.095-65.446）mg/L and（0.007-4.999）mg/L,respectively.Among these environmental factors,the greatest effect on the total ammonia criteria in seawater is pH,followed by temperatures,and then by salinity.Compared to the US ammonia criteria in seawater,the CMCrange narrows 5times and the CCCrange shrinks 10 times.Results showed that the current non-ionized ammonia criteria should be corrected as a lower value of 0.007mg/L to effectively protect the seawater species.Meanwhile,the total ammonia criteria were suggested to manage the ammonia in seawater.These provide the scientific evidence for making the ammonia standard in seawater in China.