Antibiotic Concentrations in Aquatic Environments of the African Continent: A Systematic Review and Predicted No-Effect Concentration (PNEC) Assessment

Background: Antibiotic pollution in aquatic environments is a growing global concern, posing risks to ecosystem health and human well-being. The African continent faces increasing challenges in addressing this issue, necessitating a comprehensive understanding of the current state of research and regional trends. Aim: This review synthesizes evidence on the occurrence and distribution of antibiotics in aquatic environments in the African continent, assessing concentration levels and evaluating the potential environmental and microbial risks using predicted no-effect concentrations (PNECs). Methods: A systematic search of PubMed, Scopus, Web of Science, and Google Scholar was conducted to identify relevant studies published between January 1, 2015, and November 13, 2024, reporting antibiotic concentrations in surface water, groundwater, drinking water, and wastewater from countries within the African continent. Results: The review encompassed 19 studies reporting antibiotic concentrations in aquatic environments from 8 African countries, with the majority being conducted in South Africa. Surface water was the most frequently sampled environment. Twenty-six antibiotics from various classes were identified, with sulfamethoxazole and trimethoprim being the most frequently detected. Surface water and wastewater exhibited the highest numbers of antibiotics. Antibiotic concentrations fluctuated over time, peaking in 2020 and 2021. Wastewater had the highest concentrations, with norfloxacin levels reaching up to 433.0000 µg/L, while drinking water had the lowest concentrations. In many instances, detected concentrations surpassed PNEC-ENV and PNEC-MIC values, indicating potential environmental and microbial risks. Conclusion: This review underscores the threatening high concentrations levels of antibiotic in African aquatic environments, particularly in wastewater and surface waters. The presence and levels of some antibiotics exceeding the PNEC thresholds raises concerns because they can foster the development and spread of antibiotic resistance. Antibiotic-polluted groundwater and drinking water highlight the urgent need for robust water management and treatment optimization to safeguard human health.