Strategy selection for addressing antibiotic pollution in farmland soils based on the analysis of source...

Antibiotics are emerging soil pollutants that pose serious threats to food security, ecosystems, and human health. Farmland within the monitoring area of the Yangtze River Delta Field Station for Ecological and Land Use Research, Ministry of Natural Resources of China, was selected as the study area. Through analyses of antibiotic source apportionment, risk decomposition, and the relationship between soil environmental factors and antibiotic occurrence, we conducted a comprehensive assessment of antibiotic pollution in farmland soils and proposed corresponding mitigation strategies. Thirty-nine out of the forty monitored antibiotics were detected in farmland soils, with concentrations ranging from 1.06 to 48.0 ng/g. The combined ecological risk of antibiotics in farmland soils was predominantly below the high-risk threshold (RQ < 1, accounting for 83.95 %). Sulfadimethoxine, norfloxacin and ciprofloxacin had over 60 % probability of causing moderate or high ecological risks and were the major contributors to ecological risk. Aquaculture wastewater, irrigation river water affected by reclaimed water, domestic wastewater, and livestock wastewater and manure were identified as the primary sources of antibiotics in farmland soils, contributing 33.74 %, 52.11 %, 6.59 %, and 7.56 % to the total antibiotic content, and 41.27 %, 30.60 %, 3.93 %, and 24.19 % to the ecological risk, respectively. Among soil environmental factors, Zn is the key factor most closely related to antibiotic occurrence in the study area, showing a significant positive correlation. From a source-sink perspective, this study proposed some policies and management measures that can be prioritized. Controlling and treating effluents from animal production and irrigation river water affected by reclaimed water are priority measures to reduce antibiotic input from the source. Managing Zn, Cu and preventing soil acidification are priority measures for field management. This study provides a basis for strategy selection to control antibiotic pollution in farmland soils.