Antibiotics in cultured freshwater products in Eastern China: Occurrence, human health risks, sources, and bioaccumulation potential

The adverse effects of antibiotics residues on aquaculture ecosystems and humans raised increasing concerns globally. To assess the occurrence, human health risks, sources, and bioaccumulation potential of antibiotics in cultured freshwater products in Eastern China, 12 and 13 aquaculture ponds were selected in 2018 and 2019, respectively, both covering 8 aquatic species. Concentrations of 12 commonly-used antibiotics were measured in muscle tissue of aquaculture products, water, sediment, and suspended particles. At least two antibiotics were found simultaneously in all muscle tissue samples. The concentrations of most antibiotics in freshwater cultured products were at a medium or lower level in comparison with other studies in China and worldwide, but slightly higher than the concentrations in cultured marine products. The potential risks from the intake of these aquatic products were also evaluated. The results showed limited adverse effects due to the consumption of these products with an exception of fluoroquinolone antibiotics. The bioaccumulation potential from water varied widely in different collection years, but the bioaccumulation factor (BAF) values for antibiotics were all <50 L/kg. BSAF values of antibiotics were all far below 1, except for one site in Zhejiang province in 2018, indicating that the bioavailability from surface sediments was low, in a particular pond environment. The low repeatability of BAF and BSAF calculated in two years indicated a relatively unsteady status in terms of bioaccumulation potential of cultured freshwater ponds yearly.