Antibiotic Occurrence and Associated Environmental Hazard: A Case Study of a DrinkingWater Reservoir Impacted by Wastewater Discharge

The fate and transport of 26 common human and veterinary antibiotics were investigated in a small, semi-urban watershed that is impacted by wastewater discharges. The watershed ultimately links an impacted reservoir, in which twelve of the twenty-six antibiotics were detected at concentrations up to 2 μg/L, to a downstream drinking water source. A Bayesian Maximum Entropy framework with modern spatiotemporal geostatistics was used to process information about one antibiotic, sulfamethoxazole, in this watershed and this study demonstrates the practical benefit of using field measurements and model predictions to establish a more complete map of contaminant transport. Generated maps show that the areas of greatest accumulation are within the streams where antibiotics appear to follow a pseudo-first order rate of removal from the aqueous phase. An environmental hazard assessment was then performed, and among the antibiotics studied, sulfamethoxazole, ciprofloxacin, and erythromycin were found to present the greatest environmental hazard