Occurrence of sulfonamides in fish in the lower reaches of Yangtze River, China and estimated daily intake for understanding human dietary exposure

Abstract

The occurrence and human dietary exposure to 12 sulfonamides in fish samples along the lower reaches of the Yangtze River, China, were investigated in this study. The sulfonamides residue levels of 82 collected samples (21 caught and 61 aquacultured) were analyzed. Although 12 selected sulfonamides were detected in all fish samples along the lower reaches of the Yangtze River, the residual levels of caught and aquacultured samples were both below 5 μg kg−1 in the initial growth stage of fish. And sulfadiazine (SDZ) and sulfamethoxazole (SMX) were heavily used in the peak of fish growth. During this period, 17.4% of the samples contained concentrations of total sulfonamides above the maximum residue limit (100 μg kg−1); 13.0% were between 10 and 100 μg kg−1, and the remaining (about 69.6%) were under 10 μg kg−1. Through this study, we found residual levels of sulfonamides varied in different regions and in different fish species. Yixing and Changzhou were the main areas where the highest concentrations of sulfonamides were found. Huzhou and Suzhou areas were relatively free of pollution. The highest total sulfonamides concentrations were 1634.05 μg kg−1 and 472.97 μg kg−1 in crab and bream, respectively. The sulfonamides concentrations in shrimp and perch were low. Based on the estimated daily intake (EDI) of Sulfonamides (SAs) in this study, SAs do not posed an immediate threat to human health; however, the potential risk to human safety could increase in the long run if the residual status of sulfonamides in aquatic products were left unattended.