Environmental Footprint of Antibiotics: A Multi-Source Investigation of Wastewater Systems in UAE.

Background/Objectives: Antibiotic resistance is a growing global health threat, requiring comprehensive investigations into the occurrence, distribution, and diversity of antibiotics across environmental systems. This study aimed to examine the distribution and prevalence of commonly used antibiotics in various wastewater sources across the United Arab Emirates (UAE), providing insights into potential environmental reservoirs contributing to antimicrobial resistance dissemination. Methods: Wastewater samples were collected from the outlets of three hospitals, three residential communities, and the influent and return activated sludge of two wastewater treatment plants. Samples were prepared using solid-phase extraction (SPE) and analyzed via liquid chromatography-mass spectrometry (LC-MS/MS) to quantify antibiotic concentrations and compare their distribution among sources. Results: Significant variations were observed in antibiotic concentrations across the different wastewater sources. Ciprofloxacin concentrations were highest in hospital wastewater, reaching up to 247.9 ng/mL, while cefuroxime and vancomycin ranged between 0.2 and 10.9 ng/mL across samples. Clindamycin was notably prevalent in wastewater treatment plant samples (up to 10.9 ng/mL), whereas vancomycin and cefuroxime were dominant in residential community samples, reflecting diverse antibiotic usage patterns and persistence in treatment systems. Conclusions: The findings reveal substantial antibiotic contamination in United Arab Emirates wastewater systems, underscoring the need for ongoing surveillance and regulatory measures. Continuous monitoring, coupled with effective wastewater treatment and antibiotic stewardship strategies, is critical to mitigating the environmental spread of antimicrobial resistance and safeguarding public and environmental health.