Human Health Risk Assessment of Heavy Metals in Cassava Cultivated Near 33 kV High-Voltage Power Lines in Benue State, Nigeria

Abstract

High-voltage power lines generate electromagnetic fields (EMF) that may theoretically influence soil metal bioavailability and plant uptake. Cassava, a staple root crop, can accumulate toxic metals with chronic health implications for consumers. To assess human health risks associated with heavy metal (Pb, Cd, Cu, Zn, Fe) content in cassava tubers cultivated at varying distances from a 33 kV power line in Benue State, Nigeria. Cassava tubers (TME 419) were collected at 0, 5, 10, 15, 20, and 50 m from a 33 kV power line in Apir, Makurdi. Heavy metal concentrations were determined by atomic absorption spectrophotometry. Estimated Daily Intake (EDI) and Hazard Quotient (HQ) were calculated for adult populations (body weight 60 kg, ingestion rate 0.5 kg/day). Soil homogeneity was confirmed by physicochemical analysis. Heavy metal concentrations showed irregular variations across distances with no consistent EMF-related pattern. Lead ranged from below detection to 0.118 mg/kg; cadmium from below detection to 0.012 mg/kg; copper from 0.064 to 0.104 mg/kg; zinc from 0.253 to 0.822 mg/kg. All values remained within permissible safety limits. EDI values ranged from 0.00000 to 0.00098 mg/kg/day for Pb and 0.00000 to 0.00010 mg/kg/day for Cd. HQ values for all metals across all distances were below unity (HQ < 1), with the highest being 0.28 for Pb at 0 m. No significant non-carcinogenic health risk is associated with cassava consumption from the study area. Heavy metal concentrations are primarily influenced by soil characteristics rather than EMF exposure. However, the relatively higher HQ for Pb (0.28) suggests continued monitoring is warranted.