Aquatic Life Ambient Freshwater Quality Criteria For Silver Ion In China And USA

Water quality criteria are important basis for the establishment of water qualitystandards, as well as the assessment, prediction and control of water pollution. Theresearches on the water quality criteria are insufficient in China, and the existing waterquality standards in China are determined based mainly on USA and European Unioncriteria. Silver ion is a common ion with high toxicity for aquatic organisms. Thus, it isurgent to derive water quality criteria based on water environment and biota of China.In addition, criteria values of silver have not been updated since1980in USA. Thosemight cause the damage of aquatic organisms by silver ion on.In this paper, species toxic data in aquatic freshwater were corrected base on waterhardness databases. The water criteria of silver were derived according to USA andChina biota, and their possible influencing factors were also investigated. Thefollowings results can be summarized:1)toxicity data of25aquatic species from20taxonomic families and6phyla of China and31aquatic species from30taxonomicfamilies and7phyla of USA were screened and used toxicity percentile rank method andmodified species sensitivity distribution method to obtain the water quality criteria of silver;2) there was a power function relationship between water hardness and water qualitycriteria of China and USA, the equation of acute water criteria(AWC) of silver in chinawasAWC0.0153Z0.62ug·L-1, the chronic water criteria(CWC) was0.03ug·L-1,the equation of AWC of silver in USA wasAWC0.85e0.67ln Z3.2ug·L-1, the CWCwas0.02ug·L-1;3) the water criteria values of silver in China and USA increased19and80times with the changes of water hardness, respectively;4) silver ion showedmore toxicity to invertebrate than vertebrate;5) the criteria value of both countries mayhave changes over time;6) the differences of biota and sensitive species as well as thedifferent criteria derivation method can affect water quality criteria values. This studycan play a positive role in promoting the development and improvement of the water qualitycriteria system.