Pollution characteristics and risk assessment of sulfonamide antibiotics during shallow groundwater recharge in the Shijiazhuang section of the Hutuo River

In order to identify the pollution characteristics, ecological risk and health risk of sulfa antibiotics (SAs) in groundwater during the Hutuo River recharge process, sixteen shallow groundwater samples were collected twice along the Hutuo River bank from October 2020 to October 2021. The concentrations and distribution characteristics of 20 SAs were determined using solid-phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry. The results showed that the overall pollution level of SAs in groundwater was relatively low, and only 7 of the 20 SAs were detected in groundwater during the initial recharge period. The concentration of different SAs followed the order of characteristics: sulfametoxydiazine (93.75%), sulfadiazine (37.50%), sulfachlorpyridazine (18.75%), sulfapyridine (18.75%), sulfamonomethoxine (6.25%), sulfaguanidine (6.25%), sulfacetamide (6.25%). The highest average detection concentration SAs were sulfadiazine (29 ng/L) and sulfametoxydiazine (9.2 ng/L). Due to the mixed dilution effect of high-quality South-to-North Water Diversion water, the SAs detection frequency and average detection concentration declined gradually during the groundwater recharge. The historical pollution of sewage treatment plants and agricultural livestock and poultry in this area were the leading causes of SAs pollution in groundwater. The ecological and health risk assessment results indicated that the sulfametoxydiazine and sulfadiazine were medium ecological risks, and the sulfadiazine posed a moderate risk to human health. All SAs showed no obvious ecological risk and health risk in groundwater in the later period of the recharge process.