Seasonal distribution characteristics and health risk assessment of typical antibiotics in the Harbin section of the Songhua River basin.

A method was established for coupled solid phase extraction-ultra performance liquid chromatography and mass spectrometry, to simultaneously detect 12 common antibiotics belonging to 4 types (sulfonamides, macrolides, fluoroquinolones and cephalosporins) in the Harbin section of the Songhua River basin, Northeastern China. The results showed that the 12 antibiotics monitored were all detected to varying degrees, with 100% detection rates for sulfamethoxazole (SMX), cefazolin (CFZ), ofloxacin (OFL), flumequine (FLU), azithromycin (AZI) and roxithromycin (ROX), and the highest levels were in winter, the lowest in summer. The total concentrations of all 12 antibiotics in spring, summer, autumn and winter, were 39.7, 9.6, 27.5 and 136.2 ng L-1, respectively. Seasonality was also observed in antibiotic distribution along the riverbank, with winter concentrations of all antibiotics detected upstream of the Harbin section being lower than the downstream section; in summer, except for CFZ, the concentrations of all antibiotics detected were higher upstream, than downstream of the Harbin section. Finally, the health risks to people of different ages caused by residual antibiotic contamination in the Songhua River were evaluated, and the results showed that the risk of antibiotics was far lower than 1, with no direct threat to human health established.