Keywords
Water Quality Index
Escherichia coli
trace elements
groundwater pollution
Kananga
Democratic Republic of the Congo
How to Cite
Abstract
Introduction
Access to safe drinking water remains a major public health challenge in the Democratic Republic of the Congo (DRC), particularly in peri-urban and rural areas. In Kananga and its surrounding areas, the limited coverage of public water supply has forced many households to rely on boreholes and untreated groundwater. Rapid urban expansion, inadequate sanitation infrastructure, and permeable sandy-lateritic soils increase groundwater vulnerability to surface contamination, exposing populations to chemical and microbiological health risks.
Purpose
This study evaluated the physicochemical and microbiological quality of borehole water consumed in Kananga and its surrounding areas.
Methods
Five representative borehole water samples (F1–F5) were collected during the rainy season. Physicochemical parameters, nutrient levels, and microbiological indicators were determined at the National Institute for Biomedical Research (INRB) using standard protocols. Trace metals were quantified via energy-dispersive X-ray fluorescence (ED-XRF) spectrometry. Data were evaluated against World Health Organization (WHO) drinking water guidelines. Statistical analyses, including Pearson correlation and Water Quality Index (WQI) determinations, were performed using Stata software.
Results
Most physicochemical parameters met WHO guidelines. Low electrical conductivity, total dissolved solids, and suspended solids reflected weak mineralization, while low biochemical oxygen demand, chemical oxygen demand, nutrients, and trace metals (Cu, Mn, Hg, Fe, Pb, As, Cd) indicated minimal organic and chemical pollution. However, all boreholes exhibited acidic conditions (pH range: 4.00–5.50), falling below the WHO recommended range (6.5–8.5). Significant negative correlations were observed between pH and lead (r = -0.92, p = 0.03), as well as arsenic (r = -0.90, p = 0.04), indicating that acidic conditions enhance metal mobility. The physicochemical WQI rated F4 and F5 as "Excellent" (17.98 and 24.60), F1 and F2 as "Good" (41.60 and 35.29), and F3 as "Poor" (53.44). Crucially, microbiological analyses revealed contamination across all boreholes by total coliforms (148–250 CFU/100 mL), enterococci (5–12 CFU/100 mL), and Escherichia coli (4–15 CFU/100 mL).
Conclusion
Although the groundwater exhibits acceptable physicochemical properties (aside from low pH), widespread microbiological contamination renders the water unfit for direct human consumption. Corrective measures—including pH neutralization (liming), disinfection (chlorination or UV irradiation), regular hydrochemical monitoring, and sanitary protection zones—are required before consumption.
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Copyright (c) 2026 Babadi, M. F., Bokombo, N. R., Iyeli, L. P., Mbuyi, K. J., Diesse, M. H., Kusonika, N. A., Biey, M. E., Musibono, D. E.