The Taxon-Specific Species Sensitivity and Aquatic Ecological Risk Assessment of Three Heavy Metals in Songhua River Water, China

Copper (Cu), zinc (Zn), and nickel (Ni) are essential micronutrients for aquatic life, but they produce adverse effects on aquatic organisms when environmental concentrations exceed a certain threshold. The objective of this study was to analyze the taxon-specific sensitivities of aquatic life to the three metals and assess ecological risks at exposure levels prevalent in the Songhua River, China. The results showed that sensitivities to these metals varied among different taxonomic groups, with intra-taxon sensitivities being lower than inter-taxa sensitivities, and the consistency of intra-taxon sensitivity increased from phylum to order. The maximum detected concentrations of Cu, Zn, and Ni in the Songhua River were 52.7, 166.0, and 65.3 mu g/L, respectively, which met the water quality standards set by China but exceeded the chronic criteria established by the USA. A probabilistic risk assessment based on chronic toxicity data revealed that these three metals posed an intermediate to high risk to aquatic animals, with maximum risk products of 36.4% for Cu, 14.3% for Ni, and 6.2% for Zn, respectively. These results indicate that the ecological damage of heavy metals in the Songhua River cannot be ignored.