Comparison of mercury species sensitivity distributions of freshwater biota in China and the United States
中美淡水生物区系中汞物种敏感度分布比较

Based on single-species freshwater acute toxicity data in China and the United states, species sensitivity distributions (SSDs) of vertebrates (including fish) and invertebrates (including arthropods and non-arthropod invertebrates) to mercury were constructed, and species sensitivity to mercury in these two countries were compared. The results of this study indicated that there was no significant difference between sensitivity distributions of the Chinese and American taxa. However, the hazardous concentration for 5% of the species (HC5) range of Chinese species to short-term mercury exposure was lower than that of the American species, especially for non-arthropod invertebrates. HC5 for American non-arthropod invertebrates to mercury was 7.4 times larger than that for the corresponding Chinese species. Under the 95% protection level and including all the species, the tested invertebrates were more sensitive to mercury than the vertebrates in both China and the United States. However, in the lower taxonomic classification level, the sensitivity decreased in the order of arthropod > non-arthropod invertebrates > fish in China, but the order was arthropods > fish > non-arthropod invertebrates in the United States. Therefore, in determining the water quality criteria based on the sensitivity of all the species, we should also consider the influence of SSD of individual groups. The water quality criteria derived from the species sensitivity distribution of American species may make the aquatic species in China out of protection.