Investigation of fluoroquinolones, sulfonamides and macrolides in long-term wastewater irrigation soil in Tianjin, China.

Fluoroquinolones, sulfonamides and macrolides were analyzed in soil samples collected from suburban areas in Tianjin, China. Fluoroquinolones were the predominant class of antibiotics. The mean total concentration of fluoroquinolones (33.56 μg/kg) was 30-fold higher than one of macrolides, which were the second dominant class antibiotics. Sulfonamides showed the lowest level in soil. The spatial distribution of fluoroquinolones showed wastewater irrigation was a potential source of antibiotics. The individual antibiotics levels were all below the trigger value (100 μg/kg) set by the Steering Committee of Veterinary International Committee, indicating the low risk for organisms in the agricultural soils of Tianjin.