Occurrence of Antibiotics in Water in Xiaodian Sewage Irrigation Area, Northern China

The Xiaodian sewage irrigation area in northern China has a long history of sewage irrigation. The surface water and groundwater samples were collected and analyzed in this region. All the 25 kinds of antibiotics have been detected in the surface water in this study area. The order of average detection frequency is Macrolides (MLs, 98.2%) > Fluoroquinolones (FQs, 91.3%) > Tetracyclines (TCs, 87.5%) > Sulfonamides (SMs, 75.0%). The sample with the highest concentration of antibiotics (730.19 ng/L) is located at Taiyu Drainage Canal while that with the lowest concentration (245.93 ng/L) at Xiaohe River. The type and concentration of antibiotics in SW-3 and SW-4 were almost the same, indicating the measures to prevent canal banks from seepage were able to retard their transport into the soil and groundwater system via lateral recharge. Along the Beizhang Drainage Canal, the sewage from the swine farm, the cow farm, the irrigation field and domestic usage were all discharged into the canal, so the concentration kept increasing. Along the down gradient direction of Taiyu Drainage Canal, the concentration decreased. Transport of the contaminants via lateral recharge due to lack of seepage prevention measures, therefore, poses a potential threat to the soil-groundwater system. 15 of 25 kinds of antibiotics were detected in the groundwater. The detection frequency was lower than other study areas in China The concentrations ranged from 2.75 ng/L to 114.38 ng/L with the average concentration of 27.60 ng/L.