Comprehensive ecological risk assessment method for multi-pesticide pollution in the Bohai Sea and Yellow Sea, China

Pesticide residues and their accumulation in marine environments pose potential threats to the ecosystem balance and human health. Assessment of pesticide residue levels and ecological risks in marine waters is insufficient. Therefore, we conducted a quantitative analysis of four different categories of pesticides in the surface waters of the Bohai Sea and Yellow Sea in China. A comprehensive ecological risk assessment framework was constructed based on the importance of ecosystem services, utilizing the risk quotient (RQ) and entropy weighting methods to evaluate the multi-pesticide ecological risks in the study area. Thirteen pesticides were detected in the surface waters, with total concentration levels ranging from 8.18 to 80.60 ng/L, and the herbicide Atrazine and insecticide Imidacloprid were found at the highest levels. Concentration levels were higher in the Bohai Sea than in the Yellow Sea, and the highest area was mainly located on the coast of Shandong Province, China. The ecological risk of multi-pesticide pollution was the highest in the coastal regions of Shandong and was associated with Atrazine and Acetamiprid. Source analysis suggested that triazine herbicide and neonicotinoid insecticides are predominantly land-sourced, whereas sulfonylurea herbicides are primarily atmospheric. This study provides valuable support for formulating relevant environmental protection policies and measures.