Objective To understand the distribution of enrofloxacin (ENR) residues in freshwater fish, to evaluate the dietary exposure risk to ENR for consumers through the consumption of different freshwater fish in Shanghai, and to provide a reference for controlling antibiotic residues in freshwater fish.

Methods Grass carp, Wuchang bream, pond loach, and Asian swamp eels were purchased from the markets in Shanghai. After being fed with ENR, the fish were divided into 42 batches according to their species and weight, and thereafter ENR residues in the muscles and skin of the fish were measured. In addition, a total of 44 batches of Wuchang bream, pond loach, Asian swamp eels were purchased from the markets, and the ENR residues in the muscles with or without the fish skin were measured, and the exposure risk was evaluated.

Results The average residues of ENR in skin of the freshwater fish after being fed with drugs in the 42 groups were higher than those in muscles (M=659.38 μg·kg^-1, M=460.83 μg·kg^-1; z=-2.212, P=0.027). The over-standard rates of ENR residues in the muscles with or without skin 44 batches of freshwater fish of sold in Shanghai were 36.36% and 29.55%, respectively. The median exposure, P₉₅ exposure, and maximum exposure to ENR through the consumption of the muscles with the skin for adults and children in Shanghai were higher than those through the consumption of muscles without the skin. For children, the margin of safety (MOS) for the max exposure to ENR by consuming the muscles with the skin was more than 1, while the MOS was less than 1 in all other cases for both children and adults.

Conclusion The ENR residues in the skin of freshwater fish are generally higher than those in the muscles. The risk of ENR residues in freshwater fish sold in Shanghai is within a controllable range. However, there might be a certain risk of acute exposure to ENR for children by consuming muscles with the skin of freshwater fish.