DDT contamination in water resources of some African countries and its impact on water quality and human health

Lethabo Makgoba; Amber Abrams; Martin Röösli; Guéladio Cissé; Mohamed Aqiel Dalvie

doi:10.1016/j.heliyon.2024.e28054

DDT contamination in water resources of some African countries and its impact on water quality and human health

Heliyon. 2024 Mar 20;10(7):e28054. doi: 10.1016/j.heliyon.2024.e28054. eCollection 2024 Apr 15.

Authors

Lethabo Makgoba¹, Amber Abrams², Martin Röösli^{3

4}, Guéladio Cissé^{3

4}, Mohamed Aqiel Dalvie^{1

2}

Affiliations

¹ Centre for Environmental and Occupational Health Research, School of Public Health, University of Cape Town, Health Sciences Faculty, Observatory, Cape Town, 7925, South Africa.
² Future Water Research Institute, University of Cape Town, Cape Town, 7700, South Africa.
³ Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.
⁴ University of Basel, P.O. Box, CH-4003, Basel, Switzerland.

Abstract

Dichlorodiphenyltrichloroethane (DDT) usage has been prohibited in developed nations since 1972 but is exempted for use in indoor residual spraying (IRS) in developing countries, including African countries, for malaria control. There have been no previous reviews on DDT residues in water resources in Africa. The study aimed to provide a review of available research investigating the levels of DDT residues in water sources in Africa and to assess the consequent human health risks. A scoping review of published studies in Africa was conducted through a systematic electronic search using PubMed, Web of Science, EBSCO HOST, and Scopus. A total of 24 articles were eligible and reviewed. Concentrations of DDT ranged from non-detectable levels to 81.2 μg/L. In 35% of the studies, DDT concentrations surpassed the World Health Organization (WHO) drinking water guideline of 1 μg/L in the sampled water sources. The highest DDT concentrations were found in South Africa (81.2 μg/L) and Egypt (5.62 μg/L). DDT residues were detected throughout the year in African water systems, but levels were found to be higher during the wet season. Moreover, water from taps, rivers, reservoirs, estuaries, wells, and boreholes containing DDT residues was used as drinking water. Seven studies conducted health risk assessments, with two studies identifying cancer risk values surpassing permissible thresholds in water sampled from sources designated for potable use. Non-carcinogenic health risks in the studies fell below a hazard quotient of 1. Consequently, discernible evidence of risks to human health surfaced, given that the concentration of DDT residues surpassed either the WHO drinking water guidelines or the permissible limits for cancer risk in sampled drinking sources within African water systems. Therefore, alternative methods for malaria vector control should be investigated and applied.

Keywords: Dichlorodiphenyltrichloroethane (DDT); Drinking water; Indoor residual spraying (IRS); Toxicity and cancer risk; Water sources.

Publication types

Review