Ecological risk assessment of chlorpyrifos in Laizhou Bay based on species sensitivity distributions analysis

Chlorpyrifos, a widely used organophosphorus insecticide, poses a potential hazard to marine ecosystems due to its toxicity to aquatic organisms. However, the ecological risks of chlorpyrifos to marine organisms remain unclear. This study employed species sensitivity distributions (SSDs) to assess the ecotoxicological effects of chlorpyrifos on marine ecosystems, with a focus study in Laizhou Bay, China. Our results revealed the hazardous concentration for 5 % of species (HC₅) for indigenous, non-indigenous, and all marine species were 1.341, 0.0231, and 0.0872 μg/L, respectively. The predicted no-effect concentrations (PNECs) demonstrate significant temporal variation, with short-term values of 0.6705, 0.0116, and 0.0436 μg/L, and long-term values of 0.0838, 0.0015, and 0.0055 μg/L for indigenous, non-indigenous, and all species, respectively. Non-indigenous species exhibited higher sensitivity to chlorpyrifos than indigenous species. Risk assessment based on risk quotients (RQs) revealed distinct temporal patterns: short-term RQs ranged from 0.001 to 0.094 across different species groups, while long-term RQs showed higher values ranging from 0.004 to 0.727. These findings indicated minimal short-term ecological risk, but moderate long-term risk, particularly for non-indigenous species. Our study provides compelling evidence that chlorpyrifos poses a potential threat to the ecosystem of Laizhou Bay. These findings offer crucial scientific data for establishing water quality standards for chlorpyrifos in China and developing effective management strategies for pesticide pollution in marine environments.