Comprehensive analysis and risk assessment of Antibiotic contaminants, antibiotic-resistant bacteria, and resistance genes: Patterns, drivers, and implications in the Songliao Basin

Abstract

The pervasive use of antibiotics has raised substantial environmental concerns, especially regarding their temporal and spatial distribution across diverse water systems. This study addressed the gap in comprehensive research on antibiotic contamination during different hydrological periods, focusing on the Jilin section of the Songliao Basin in Northeast China, an area with severe winter ice cover. The study examined the occurrence, distribution, influencing factors, and potential ecological risks of prevalent antibiotic contaminants. Findings revealed antibiotic concentrations ranging from 239.64 to 965.81 ng/L, with antibiotic resistance genes (ARGs) at 5.22 × 10⁻² 16S rRNA⁻¹ and antibiotic-resistant bacteria (ARB) up to 5.76 log₁₀ CFU/mL. Ecological risk assessments identified significant risks to algae from oxytetracycline, erythromycin, and amoxicillin. Redundancy analysis and co-occurrence networks with ordinary least squares (OLS) demonstrated that the dispersion of ARGs and ARB is significantly influenced by environmental factors such as total organic carbon (TOC), total phosphorus (TP), total nitrogen (TN), fluoride (F⁻), and nitrate (NO₃⁻). These elements, along with mobile genetic elements (MGEs), play crucial roles in ARG patterns (R² = 0.94, p ≤ 0.01). This investigation offers foundational insights into antibiotic pollution dynamics in cold climates, supporting the development of targeted mitigation strategies for aquatic systems.