Environmental occurrence, ecotoxicity, and management perspectives of β-lactam antibiotics.

β-Lactams are the most widely prescribed antibiotic class globally, comprising penicillins, cephalosporins, carbapenems, and monobactams. Their continual release to the environment raises concerns about both direct ecotoxicity and potential indirect effects on ecosystem function. This review highlights three key findings; 1) environmental concentrations can exceed predicted no-effect concentrations for resistance selection; for example ceftriaxone had been reported 6160 µg/L in wastewater influent and 4150 µg/L in effluent in India, indicating that many β-lactams have removal efficiency below 33%, 2) ecotoxicity data show that cyanobacteria ( e.g. Microcystis aeruginosa, EC50 0.0037 mg/L for amoxicillin) are ≥ 1,000-fold more sensitive than macrofauna, and that chronic exposure at ng-µg/L levels may promote selection of antimicrobial resistance and facilitate horizontal gene transfer of these genes and 3). β-lactam resistance genes (blaCTX-M, blaNDM, blaOXA) are ubiquitous in wastewater and manure-amended soils and can persist even after the degradation of the parent compounds. Collectively, these finding indicates that β-lactam antibiotics pose significant risks to aquatic and soil ecosystems by contributing to the proliferation and maintenance of antimicrobial resistance in environmental reservoirs. The widespread environmental occurrence and persistence of β-lactams, along with associated resistance determinants, represent emerging One Health concerns. This narrative review synthesizes current literature on the ecotoxicological effects of β-lactam antibiotics, focusing on their major environmental sources, distribution across environmental matrices, impacts on non-target organisms, and emerging strategies to mitigate their environmental burdens. We further emphasize cross-disciplinary solutions spanning engineering, microbial ecology, policy, identify critical research gaps, and propose pragmatic pathways to reduce environmental selection pressure from β-lactams.