Occurrence of Pharmaceutically Active Compounds and Potential Ecological Risks in Wastewater from Hospitals and Receiving Waters in Sri Lanka.

The presence of pharmaceutically active compounds (PACs) in the environment and their associated hazards is a major global health concern; however, data on these compounds are scarce in developing nations. In the present study, the existence of 39 non-antimicrobial PACs and six of their metabolites in wastewater from hospitals and adjacent surface waters in Sri Lanka was investigated from 2016 to 2018. The highest amounts of the measured chemicals, including the highest concentrations of atorvastatin (14,620 ng/L) and two metabolites, mefenamic acid (12,120 ng/L) and o-desmethyl tramadol (8700 ng/L), were detected in wastewater from the largest facility. Mefenamic acid, gemfibrozil, losartan, cetirizine, carbamazepine, and phenytoin were detected in all the samples. The removal rates in wastewater treatment were 100% for zolpidem, norsertaline, quetiapine, chlorpromazine, and alprazolam. There was substantial variation in removal rates of PACs among facilities, and the overall data suggest that treatment processes in facilities were ineffective and that some PAC concentrations in the effluents were increased. The estimated risk quotients revealed that 14 PACs detected in water samples could pose low to high ecological risk to various aquatic organisms. Compounds such as ibuprofen, tramadol, and chlorpromazine detected in untreated and treated wastewater at these facilities pose a high risk to several aquatic organisms. Our study provides novel monitoring data for non-antimicrobial PAC abundance and the associated potential ecological risk related to hospitals and urban surface waters in Sri Lanka and further offers valuable information on pre-COVID-19 era PAC distribution in the country. Environ Toxicol Chem 2022;41:298-311. © 2021 SETAC.

The association between antimicrobials and the antimicrobial-resistant phenotypes and resistance genes of Escherichia coli isolated from hospital wastewaters and adjacent surface waters in Sri Lanka.

The presence of antimicrobials, antimicrobial-resistant bacteria (ARB), and the associated antimicrobial resistance genes (ARGs) in the environment is a global health concern. In this study, the concentrations of 25 antimicrobials, the resistance of Escherichia coli (E. coli) strains in response to the selection pressure imposed by 15 antimicrobials, and enrichment of 20 ARGs in E. coli isolated from hospital wastewaters and surface waters were investigated from 2016 to 2018. In hospital wastewaters, clarithromycin was detected at the highest concentration followed by sulfamethoxazole and sulfapyridine. Approximately 80% of the E. coli isolates were resistant, while 14% of the isolates exhibited intermediate resistance against the tested antimicrobial agents. Approximately 61% of the examined isolates were categorized as multidrug-resistant bacteria. The overall abundance of phenotypes that were resistant toward drugs was in the following order: ß-lactams, tetracycline, quinolones, sulfamethoxazole/trimethoprim, aminoglycosides, and chloramphenicol. The data showed that the E. coli isolates frequently harbored blaTEM, blaCTX-M, tetA, qnrS, and sul2. These results indicated that personal care products were significantly associated with the presence of several resistant phenotypes and resistance genes, implying their role in co-association with multidrug resistance. Statistical analysis also indicated a disparity specific to the site, treatment, and year in the data describing the prevalence of ARB and ARGs and their release into downstream waters. This study provides novel insights into the abundance of antimicrobial, ARB and ARGs in Sri Lanka, and could further offer invaluable information that can be integrated into global antimicrobial resistance databases.