Nontargeted Screening of Contaminants of Emerging Concern in the Glen Valley Wastewater Treatment Plant, Botswana.

There is growing concern about the prevalence and impact of contaminants of emerging concern (CECs). The environmental monitoring of CECs has, however, been limited in low- and middle-income countries due to the lack of advanced analytical instrumentation locally. In the present study we employed a nontargeted and suspect screening workflow via liquid chromatography coupled with high-resolution mass spectrometry (HRMS) to identify known and unknown pollutants in the Glen Valley wastewater treatment plant, Botswana, complemented by analysis of groundwater samples. The present study represents the first HRMS analysis of CECs in water samples obtained in Botswana. Suspect screening of 5942 compounds qualitatively identified 28 compounds, including 26 pharmaceuticals and two illicit drugs (2-ethylmethcathinone and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol). Nontargeted analysis tentatively identified the presence of 34 more compounds including (5ξ)-12,13-dihydroxypodocarpa-8,11,13-trien-7-one, 12-aminododecanoic acid, atenolol acid, brilliant blue, cyclo leucylprolyl, decanophenone, DL-carnitine, N,N'-dicyclohexylurea, N4-acetylsulfamethoxazole, NP-003672, and 24 polyethylene glycol polymers. The highest number of detections were in influent wastewater (26 CECs) followed by effluent wastewater (10 CECs) and, lastly, groundwater (4 CECs). Seventeen CECs detected in the influent water were not detected in the effluent waters, suggesting reduced emissions due to wastewater treatment. Two antiretroviral compounds (abacavir and tenofovir) were detected in the influent and effluent sources. This suggests that wastewater treatment plants are a major pathway of chemical pollution to the environment in Botswana and will help inform prioritization efforts for monitoring and remediation that is protective of these key ecosystems. Environ Toxicol Chem 2024;43:52-61. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Emerging contaminant exposure to aquatic systems in the Southern African Development Community.

The growing production and use of chemicals and the resultant increase in environmental exposure is of particular concern in developing countries where there is rapid industrialization and population growth but limited information on the occurrence of emerging contaminants. Advances in analytical techniques now allow for the monitoring of emerging contaminants at very low concentrations with the potential to cause harmful ecotoxicological effects. Therefore, we provide the first critical assessment of the current state of knowledge about chemical exposure in waters of the Southern African Developmental Community (SADC). We achieved this through a comprehensive literature review and the creation of a database of chemical monitoring data. Of the 59 articles reviewed, most (n = 36; 61.0%) were from South Africa, and the rest were from Botswana (n = 6; 10.2%), Zimbabwe (n = 6; 10.2%), Malawi (n = 3; 5.1%), Mozambique (n = 3; 5.1%), Zambia (n = 2; 3.4%), Angola (n = 1; 1.7%), Madagascar (n = 1; 1.7%), and Tanzania (n = 1; 1.7%). No publications were found from the remaining seven SADC countries. Emerging contaminants have only been studied in South Africa and Botswana. The antiretroviral drug ritonavir (64.52 µg/L) was detected at the highest average concentration, and ibuprofen (17 times) was detected most frequently. Despite being the primary water source in the region, groundwater was understudied (only 13 studies). High emerging contaminant concentrations in surface waters indicate the presence of secondary sources of pollution such as sewage leakage. We identify research gaps and propose actions to assess and reduce chemical pollution to enable the SADC to address the Sustainable Development Goals, particularly Goal 3.9, to reduce the deaths and illnesses from hazardous chemicals and contamination. Environ Toxicol Chem 2022;41:382-395. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.