Constructing model-averaging species sensitivity distributions of Phenanthrene based on reproductive fitness: Implications for assessing ecological risk in urban watershed.

The challenge in optimizing the method of constructing species sensitivity distribution (SSD) remains. In this study, a model-averaging SSD was created to evaluate the ecological risk of Phenanthrene (PHE) in urban watershed based on reproductive fitness. Specifically, concentrations of PHE were measured in surface water samples collected from various watersheds of Wuhan, including five lake watersheds and the Wuhan reach of the Yangtze River and Han River. The reproductive endpoint of aquatic species was calculated to be most sensitive to PHE exposure, with the value of predict no-effect concentration (PNEC) at 0.19 μg/L. The results of probabilistic assessment methods, including joint probability curve (JPC), overall risk probability (ORP), and distribution-based quotient (DBQ), indicated that the ecological risks of PHE in large lakes have dropped significantly with distance from the downtown area of Wuhan, and the long-term effects of industrial activities may increase the risks in the lake watersheds. Basically, the ecological risks in Yangtze River are negligible; however, there is a relatively high risk of PHE in the Han River and some lake watersheds. The cos θ similarity analysis indicated the Yangtze River is strongly connected to the low-risk lake watersheds, and that in part reflects the risk in the Yangtze River being controlled by its surrounding these lake watersheds.