Do pyrethroid pesticide residues in Chinese mitten crab aquaculture areas have an impact on the ecological environment? --A case study of Yangcheng Lake.

Pyrethroid pesticides are widely used in agriculture, aquaculture, and daily life in China, leading to concerns about their environmental residues. However, there is limited information available regarding the compositional distribution, bioaccumulation, and associated health and environmental risks of pyrethroids in the aquaculture areas of Eastern China. This study investigated the residues, distribution, and risk assessment of pyrethroids including deltamethrin, permethrin, fenvalerate, cypermethrin and bifenthrin in Yangcheng Lake using solid-phase extraction and gas chromatography-tandem mass spectrometry. The risk assessment of water, sediment, and aquatic products of Yangcheng Lake was conducted using various evaluation methods. The results revealed that pyrethroids were found at higher levels in both water and sediment in Yangcheng Lake with some seasonal variations observed in their distribution patterns. Compared with other watersheds in China, typical aquaculture areas of the Yangtze River Delta showed higher detection rates and quantities of pyrethroid pesticides. Ecological risk assessments indicated high risks to the environment from all five tested pyrethroids at Yangcheng Lake; deltamethrin posed the highest risk among them. Dietary assessment results showed no risks associated with aquatic products from Yangcheng Lake but drinking water at certain sites presented unacceptable health risks.