Research on the Characteristics and Ecological Risks of Antibiotic Pollution in Household Garbage Leachate Treatment Systems

Concentrations of 39 antibiotics from five classes were determined in the leachate treatment system and surrounding groundwater of a municipal landfill in Hohhot using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results show that 12 antibiotics from 3 classes were detected in raw leachate, with concentration ranging from ND to 40 155.40 ng·L^-1 and detection rate between 33.33% and 100.00%. Among the detected antibiotics, quinolones (QNs) were predominant, accounting for 82.66% of the total. In the surrounding groundwater, eight antibiotics from 3 classes were detected at concentrations ranging from ND to 0.037 0 ng·L^-1, with sulfonamides (SAs) being the most prevalent (71.29%). Seasonally, antibiotic concentrations in leachate. In general, the concentration of antibiotics in the leachates followed the order of autumn > spring > summer, while in groundwater it showed the order of summer > autumn > spring. Ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) exhibited varying removal efficiencies, with NF and RO achieving superior antibiotic removal. Spearman correlation analysis indicates that the concentration of sulfadiazine (SDZ) was significantly and positively correlated with Zn, Ni, Cr, total nitrogen (TN), and chemical oxygen demand (COD), while the concentration of norfloxacin (NOR) was significantly and positively correlated with the concentration of total organic carbon (TOC). Azithromycin (AZM) and roxithromycin (ROX) showed significantly positive correlations with Ni, Cr, total phosphorus (TP), TN, and COD. Ecological risk assessment suggestes that sulfadimethoxine (SD) and ROX in the groundwater posed low ecological risks, and AZM presented a low risk of resistance development. These findings provide essential data support for the antibiotic pollution control and environmental management in the waste disposal sector.