Metagenomic characterization of antibiotic resistance genes and human bacterial pathogens in groundwater from agricultural, landfill, and hazardous waste disposal sites (HWDS) sources: Drivers, risks, and source tracking.

Agricultural sources, landfills, and hazardous waste disposal sites (HWDS) are major hotspots for the spread of groundwater antibiotic resistance genes (ARGs) and human bacterial pathogens (HBPs). However, there is a lack of systematic understanding regarding the environmental behavior of groundwater ARGs, the pathogenic risks of HBPs, and the relative contribution mechanisms of different sources, presenting critical scientific challenges for developing targeted groundwater pollution control strategies. To address this, this study collected 26 groundwater metagenomic samples to characterize the composition, influencing factors, and health risks of ARGs and HBPs near key ARG reservoirs, and constructed a source-tracking indicator system. The research identified 16 clinically critical high-risk ARGs (e.g., tetM, sul1) and 14 priority HBPs (e.g., Escherichia coli, Klebsiella pneumoniae) associated with severe human diseases and high transmissibility. Screening ARG source-specific indicators demonstrated high accuracy in predicting contributions from artificially mixed sources (prediction errors < 4 %). Validation with real groundwater samples showed that landfills contributed more significantly to groundwater ARGs pollution than other sources. This study deepens our understanding of antibiotic resistance risks in groundwater near key ARG reservoirs and provides a robust framework for tracing ARGs in complex groundwater environments by integrating microbe-gene-environment interactions across multiple pollution sources.