Occurrence, distribution and bioaccumulation of antibiotics in the Haihe River in China.

The occurrence, distribution and bioaccumulation of 22 antibiotics, including eight fluoroquinolones (FQs), nine sulfonamides (SAs) and five macrolides (MLs), in the Haihe River were investigated. Surface water, sediment and fish samples were analyzed by HPLC-MS/MS. Ofloxacin, sulfamethoxazole, sulfadiazine, erythromycin and roxithromycin were found in all surface water samples. SAs were the predominant antibiotics in surface water samples in the mainstream of Haihe River, with the maximum concentration of 201 ng L(-1) for sulfamethoxazole. Compared with Haihe River, higher concentrations of antibiotics were found in the surface water samples in the Dagu and Chentaizi Drainage Rivers. The antibiotics pollution in the mainstream of Haihe River may derive from its tributaries, whereas the wastewater from fish ponds was not the main source of FQs, SAs and MLs in the river water. In sediment samples, FQs were the most frequently detected antibiotics and their concentrations were much higher than SAs and MLs. The high concentrations and detection frequencies of FQs in sediments indicate that sediments are an important reservoir for FQs as they are strongly adsorbed onto sediments. Ciprofloxacin and erythromycin exhibited potential bioaccumulation in crucian carp, with mean bioaccumulation factors of 3262 L kg(-1) and 4492 L kg(-1), respectively.