Abstract
Pyrethroid pesticides like deltamethrin and cypermethrin are widely used in aquaculture, yet their food safety implications remain understudied. This research investigated their acute toxicity, tissue-specific bioaccumulation, and elimination patterns in crucian carp (Carassius auratus). Acute toxicity tests determined 96 h LC50 values of 9.68~11.22 ng·mL⁻(1) (deltamethrin) and 3.12~5.01 ng·mL⁻(1) (cypermethrin) with 95% confidence intervals. During 8-day exposures to sublethal concentrations (1/10 and 1/100 of LC50), deltamethrin accumulated predominantly in the liver (peak: 21.98 ng·g⁻(1) at 1.04 ng·mL⁻(1), standard deviation is 0.064 ng·mL⁻(1)), whereas cypermethrin concentrated in muscle (peak: 9.76 ng·g⁻(1) at 0.40 ng·mL⁻(1), standard deviation is 0.138 ng·mL⁻(1)). A 7-day elimination phase revealed faster clearance of low-concentration residues, with >50% removal within 24 h in all tissues. Bioconcentration factors were highest in the liver (36.62 for deltamethrin) and muscle (45.17 for cypermethrin). These results highlight tissue-specific accumulation risks and rapid initial elimination, providing critical data to optimize pesticide-dosing protocols, mitigate ecotoxicological threats, and enhance food safety in aquaculture systems.