Effects of dissolved organic matter, feeding, and water flow on the bioconcentration of diclofenac in crucian carp (Carassius auratus).

Diclofenac (DCF), a prevalent anti-inflammatory drug, is frequently detected in aquatic organisms. However, little is known about the environmental factors that affect the bioconcentration of DCF in aquatic environments. Here, we firstly investigated the bioconcentration of DCF by crucian carp (Carassius auratus) following aqueous exposure (3.57, 14.5, and 71.8 μg L-1) for 21 days. DCF can accumulate in crucian carp, and the maximum bioconcentration factors (BCFs) of 121 L kg-1 in the liver, 52.3 L kg-1 in the gills, and 46.8 L kg-1 in the muscle were always found at 3.57 μg L-1 after 14 days of exposure. Secondly, the influences of dissolved organic matter (DOM), feeding, and water flow on the bioconcentration of DCF were determined at the nominal concentration of 4 μg L-1 for 14 days. The BCFs of DCF in various fish tissues decreased by 0.5-85% with the increasing DOM concentrations. Feeding also led to lower body burden of DCF in fish tissues (6-55%) with the increasing food amount. In hydrodynamic experiment, the BCFs of DCF decreased by15-57% at most in various fish tissues. Collectively, our results demonstrated the bioconcentration of DCF in fish can be influenced by various environmental factors, which should be considered in the risk assessment of pharmaceuticals.