The Emerging Threat of Antibiotic Residues in the Aquatic Environments of East Africa: A Systematic Review

Background: Antibiotic contamination of aquatic ecosystems, driven by poor waste management, is a critical public and environmental health concern in East Africa, though comprehensive regional data remain limited. Objectives: This systematic review synthesizes evidence on the presence, concentration, and impact of antibiotic residues in East African water bodies. Methods: A systematic review was conducted in accordance with PRISMA guidelines. PubMed, Scopus, and Google Scholar were searched for studies published between 2010 and 2023 that reported the detection or quantification of antibiotic residues in aquatic environments of East African countries. Data on antibiotic classes, water matrices, detection frequencies, concentration ranges, analytical methods, and limits of detection were extracted and synthesized descriptively. Results: Of the 5,551 records identified, 20 studies met inclusion criteria. All eligible studies originated from Kenya (70%), Uganda (20%), and Ethiopia (10%). A total of 49 antibiotics belonging to 11 classes were investigated across wastewater, rivers, lakes, surface water, and groundwater. Antibiotics concentration ranged from 0.0008 to 240 830 μg/l, with the highest levels detected in wastewater effluents. Sulfamethoxazole was the most frequently detected antibiotics (80.36%), followed by norfloxacin and enoxacin. Overall, 73.5% (36/49) of detected antibiotics exceeded 0.1 μg/l, a concentration associated with ecological risk and AMR selection pressure. Conclusion: Antibiotic residues are widely present in East African aquatic environments at concentrations that may pose significant ecological and public health risks. Strengthened wastewater treatment, routine environmental monitoring, and regionally coordinated antibiotic stewardship and regulatory measures are urgently needed.