EFFECTS OF CARCINOGENIC AND NON – CARCINOGENIC RISK DUE TO HEAVY METAL CONCENTRATION IN SOIL FROM SAMPLES COLLECTED FROM NORTHERN BORNO, BORNO STATE , NIGERIA

ABSTRACT

This study assessed the concentrations of five carcinogenic heavy metals—arsenic, cadmium, lead, mercury, and nickel—in 20 soils, 20 water, and 20 fish samples collected from six Local Government Areas in Borno State, Nigeria. Using Atomic Absorption Spectroscopy (AAS), the mean concentrations of lead from 0.10–2.8 mg/kg in soil, all exceeding the WHO limits. Carcinogenic and radiological risk assessments revealed that Excess Lifetime Cancer Risk (ELCR) values for some areas were significantly higher than the acceptable limit of 1×10⁻⁴, indicating potential health threats to residents. Radiological indices such as Raeq, Hex, and AEDE were also evaluated, with Raeq values in soil peaking at 300 Bq/kg, surpassing the safe limit of 370 Bq/kg. The study concludes that mining and agricultural activities contribute significantly to heavy metal accumulation. The combined chemical and radiological hazard assessment highlight a multi-pathway health risk through contaminated soil. The research emphasizes the urgent need for routine environmental monitoring and strict enforcement of pollution control laws to safeguard public health.