Drinking Water Quality Assessment in Sub-Saharan Africa: The Case of Disinfection Byproducts in Ghana

Abstract

While disinfection is the first goal of drinking water processes, challenges persist due to the unintended formation of disinfection byproducts (DBPs). Seven treatment plants accounting for 65% of the total supply from surface water treatment facilities in Ghana were selected for the assessment of regulated and emerging DBPs. Results from five sampling rounds reveal significant variations in dissolved organic carbon (DOC) in raw waters, ranging from 1.6 to 16 mgCL–1. DOC removal varied widely (14–90%). The trihalomethane concentrations (THM4) fall below Ghana standards and WHO recommendation; however, some particularly at Weija and Barekese were elevated (45–103 μg L–1), occasionally exceeding EU or USEPA regulatory thresholds. Nonregulated DBPs were detected at varying levels in the order haloacetaldehydes (0.5–18 μg L–1), haloacetonitriles (0.2–10.4 μg L–1), haloketones (0.4–12 μg L–1), haloacetamides (0.2–12 μg L–1), iodinated trihalomethanes (63 ng/L to 4.7 μg L–1), and halonitromethanes (12 ng L–1 to 2.5 μg L–1). Relative cytotoxicity assessment indicates a high contribution from iodinated DBPs reaching up to 50% of the relative cytotoxicity with iodoacetonitrile as the principal contributor. This study, by completing the first DBP analysis in Ghana, fills a major data gap and provides a baseline for development and health risk mitigation strategies in low-resource settings.