Lead-contaminated groundwater exposes residents to health risks in Makululu, Zambia.

Abstract

Groundwater contamination by lead (Pb) occurs commonly in historically mined regions and presents health risks to exposed residents. Poor documentation of elevated Pb levels in underserved regions prevents the development of environmental contamination policies and interventions. This study investigates Pb contamination and associated carcinogenic and non-carcinogenic health risks in Makululu, a large compound near the former Pb mine in Kabwe City, Zambia. We analyzed 34 drinking groundwater samples from hand pump boreholes (n = 21) and shallow wells (n = 13). Pb concentrations exceeded WHO and USEPA standards for safe drinking in 100% of boreholes (median = 0.15 mg/L) and 77% of shallow wells (median = 0.06 mg/L). Linear regression analysis identified temperature and depth as key predictors of Pb concentrations, with higher temperatures correlating with increased Pb levels (p = 0.008), and deeper boreholes (50-100 m) exhibiting significantly higher Pb concentrations (p = 0.007) than shallow wells (10 m). Health risk assessments revealed that adults consuming borehole water had an average daily dose of 0.005 mg/kg/day of Pb exceeding WHO thresholds, with hazard quotients (HQ > 1) indicating non-carcinogenic risks. The findings highlight the urgent need for policies to mitigate environmental pollution, enforce water quality standards to reduce Pb levels and protect public health in Makululu.