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Abstract: Water samples were collected from 19 sampling sites along the Huangpu River in June and December 2009. The occurrence, distribution and seasonal variation of 22 antibiotics, including four tetracyclines, three chloramphenicols, two macrolides, six fluoroquinolones, six sulfonamides and trimethoprim were investigated. It was found that all 19 sampling sites were contaminated by antibiotics. Four antibiotics (sulfamerazine, norfloxacin, fleroxacin and sarafloxacin) were not detected. The detection frequencies of the other 18 antibiotics were in the range of 5.3–100%. The median concentrations of the detected antibiotics ranged from quantification limits to 36.71ngL−1 (tetracycline) in June and to 313.44ngL−1 (sulfamethazine) in December. The number of detected antibiotics and the overall antibiotic concentrations were higher in December than in June due to the different river flow conditions. Different dominant antibiotics were observed for each group of antibiotics between June and December. Higher total concentrations of veterinary antibiotics such as tetracyclines were observed in suburban sampling sites than in unban sites, indicating the role of livestock and agricultural activities as an important source of antibiotic contamination. [ABSTRACT FROM AUTHOR]

The prevalence of antibiotic resistance genes (ARGs) and their relationship with antibiotics in the surface waters of the Huangpu River and the drinking water sources of Shanghai, China, were investigated. 39 ARGs, including four sulfonamide ARGs, 23 tetracycline ARGs, four chloramphenicol ARGs, five β–lactam ARGs and three penicillin ARGs were targeted in this study. Two sulfonamide ARGs (sul I and sul II), eight tetracycline ARGs (tet(A), tet(B), tet(C), tet(G), tet(M), tet(O), tet(W) and tet(X)), and one β–lactam ARG (TEM) were detected to be present in water samples by polymerase chain reaction (PCR), with the detection frequencies ranging from 42.86% to 100%. The average concentrations of the 11 ARGs ranged from 3.66×101 copy/mL (tet(B)) to 1.62×105 copy/mL (sul II), quantified by quantitative real-time PCR (QPCR). The number of detected ARGs and the ARG concentrations were generally higher in suburban sampling sites than in urban sites. Being in or near suburban rural areas, some raw drinking water sources were observed to have comparatively higher ARG contamination, drawing an urgent attention for the concern of public health. Generally consistent relations were observed between the concentrations of tet genes and the tetracycline levels and between the concentrations of sul genes and the sulfonamide levels. [ABSTRACT FROM AUTHOR]