Difference of Species Sensitivities for Aquatic Life Criteria in China and the USA

Abstract

Recently, China has commenced water quality criteria (WQC) research using the species sensitivity distribution (SSD) method. However, it is difficult to obtain sufficient toxicity data on native species for thousands of contaminants. In this study, the feasibility of deriving aquatic life criteria using toxicity data from non-native species was analyzed (taking the USA as an example). Firstly, 10 pollutants [As(Ⅲ), Cr(Ⅵ), Hg, Cu, Pb, Zn, nitrobenzene, parathion, chlorpyrifos, tributyltin] with plenty of toxicity data (at least 3 Phyla and 8 Families) both in China and the USA were selected based on the recommended aquatic life criteria of 58 pollutants by the US EPA. Secondly, the two-sample Kolmogorov-Smirnov (K-S) test and comparison method of important points of HC5 and HC50 (hazardous concentrations for 5% of the species and 50% of the species) were used to determine the difference of species sensitivity between China and the USA. The result of two-sample K-S test showed that the difference of species sensitivity to Cu, chlorpyrifos and tributyltin between the two countries was significant (P<0.05). Additionally, there were significant differences for HC5 values [Cr(Ⅵ), chlorpyrifos] between the two countries, as well as the HC50 (chlorpyrifos). As a result, there were significant differences for the species sensitivity to some pollutants [Cr(Ⅵ), chlorpyrifos, etc.] between China and the USA. Therefore, in this situation, "over-protection" or "non-protection" may happen when using the criteria values or the toxicity data of American species directly to protect the Chinese native species.