Determination of Heavy Metal Concentrations in Borehole Water Samples from Selected Communities in Enugu State

Access to clean and uncontaminated groundwater remains a critical public health concern across many communities in South East Nigeria. This study determined the concentrations of selected heavy metals, specifically lead, cadmium, iron, zinc, copper, and manganese, in borehole water samples collected from five communities in Enugu North Local Government Area. Water samples were collected in triplicate from twenty boreholes and analysed using atomic absorption spectrophotometry following standard acid digestion procedures. Physicochemical parameters including pH, turbidity, electrical conductivity, and total dissolved solids were also assessed. Lead concentrations in three of the sampled boreholes exceeded the WHO guideline value of 0.01 mg/L, reaching a maximum of 0.038 mg/L. Cadmium was detected in seven borehole samples at levels above the permissible limit, with values ranging from 0.006 to 0.021 mg/L. Iron concentrations in several samples exceeded the aesthetic guideline of 0.3 mg/L but remained within limits considered acutely toxic. Zinc, copper, and manganese were within acceptable ranges in most samples. The pH of sampled water ranged from 5.8 to 7.4, indicating mild acidity in some boreholes. Electrical conductivity values correlated significantly with total dissolved solids measurements. The presence of elevated lead and cadmium levels is attributed to geological factors and proximity to informal refuse dumps. The findings highlight the need for regular water quality monitoring and community-level water treatment interventions to protect public health in rural Enugu State.

Keywords: heavy metals, borehole water, atomic absorption spectrophotometry, water quality, Enugu State