Pyrethroid insecticides are widely used in aquaculture and agriculture, yet their occurrence and associated risks in different types of aquaculture ponds remain poorly characterized. This study investigated the contamination patterns, bioaccumulation potential, and both ecological and human health risks of eight pyrethroids in water, sediment, and aquaculture species (grass carp, crayfish, and Chinese mitten crab) from Honghu Lake, a major aquaculture region in the Yangtze River Basin, China. Pyrethroids were ubiquitously detected across all matrices, with distinct spatiotemporal variations. Allethrin dominated in water (up to 217.19 ng/L), while tetramethrin prevailed in sediment (up to 7.47 ng/g dw). In biota, cypermethrin and deltamethrin were the predominant residues in muscle tissues, with some samples exceeding EU maximum residue limits (MRLs). Ecological risk assessment based on risk quotients (RQs) revealed that allethrin, tetramethrin, and bifenthrin posed high risks to aquatic organisms, particularly algae and fish, highlighting their potential to disrupt aquatic food webs. In contrast, sediment toxicity units (TUs) for Hyalella azteca remained below 1, suggesting limited acute sediment toxicity. Human dietary risk assessment indicated negligible acute and chronic health effects under normal consumption scenarios, although cumulative exposure and MRL exceedances in certain samples warrant continuous monitoring. This study provides the first integrated assessment of pyrethroid transfer along the “environment–biota–human” continuum in a multi-species aquaculture system. Our findings identify allethrin, tetramethrin, and bifenthrin as priority pollutants for ecological management and provide a scientific basis for region-specific pollution control and risk management, supporting the green transformation of freshwater aquaculture in the Yangtze River Basin and similar intensive farming regions worldwide.
Zheng et al. (Fri,) studied this question.