An Assessment of Heavy Metal Contamination and Health Risk in Borehole Water from Mining-Impacted Communities of Chingola District, Zambia

Abstract

Background: Groundwater is a vital resource in Chingola District, Zambia, but its safety is critically threatened by intensive copper and cobalt mining. This study provides a comprehensive assessment of borehole water quality in three mining-proximal communities (Nchanga South, Kasompe, Mutenda), evaluating physicochemical parameters, heavy metal contamination, and associated human health risks.

Methods: A cross-sectional study was conducted, collecting water samples from ten strategically selected boreholes during the dry season. Standard analytical methods were employed: pH, Electrical Conductivity (EC), and Total Dissolved Solids (TDS) were measured electrometrically; turbidity and Total Suspended Solids (TSS) via nephelometry; sulphates by spectrophotometry; and heavy metals (Cu, Co, Zn, Pb, Ni, Fe) using Atomic Absorption Spectrometry (AAS). Data were compared against World Health Organization (WHO) and Zambia Bureau of Standards (ZABS) guidelines. A descriptive statistical analysis was performed, and the Heavy Metal Pollution Index (HPI) was calculated to assess overall contamination.

Results: Results revealed systemic water quality issues. The water was slightly acidic (mean pH = 6.31 ± 0.38), enhancing metal solubility. Turbidity (1.59-10.5 NTU) and TSS (17-51 mg/L) exceeded limits in 20% of samples, indicating particulate contamination. Critically, heavy metal analysis showed severe contamination: lead (Pb) concentrations reached 0.444 mg/L (44 times the WHO limit) and nickel (Ni) reached 0.539 mg/L (exceeding the 0.07 mg/L limit). The HPI for several boreholes far exceeded the critical value of 100. In contrast, Copper (Cu), Zinc (Zn), and Sulphates were within permissible limits.

Conclusion: Borehole water in Chingola is not safe for consumption without treatment. The significant exceedance of Pb and Ni levels, coupled with low pH, poses severe health risks, including neurological damage and carcinogenic effects. This study underscores an urgent public health crisis. Immediate interventions—including robust monitoring, installation of centralized or point-of-use filtration systems, and stringent enforcement of environmental regulations on mining activities—are imperative to safeguard community health.

Keywords: Groundwater Pollution, Acid Mine Drainage, Heavy Metal Pollution Index, Health Risk Assessment, Copperbelt, Konkola Copper Mines, Water Security.

DOI: 10.7176/JEP/16-13-01

Publication date: December 30th 2025