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

Kgato P. Selwe, J. Brett Sallach, Caroline E.H. Dessent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)52-61
Number of pages10
JournalEnvironmental Toxicology and Chemistry
Issue number1
Early online date5 Dec 2023
Publication statusPublished - 1 Jan 2024

Bibliographical note

Funding Information:
The authors gratefully acknowledge the Department of Tertiary Education Funding in Botswana for providing a student scholarship for Kgato P. Selwe. The York Centre of Excellence in Mass Spectrometry, used for the HRMS work, was created thanks to a major capital investment through Science City York, supported by Yorkshire Forward with funds from the Northern Way Initiative, and has more recently received additional support from the Engineering and Physical Sciences Research Council and Biotechnology and Biological Sciences Research Council.

Publisher Copyright:
© 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.


  • Contaminants of emerging concern
  • Emerging contaminants
  • High-resolution mass spectrometry
  • Nontargeted analysis
  • Suspect screening
  • Wastewater

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