Human health risk assessment of metals and metalloid in food crops harvested from crude oil impacted community in Niger Delta, Nigeria

This study evaluated the human health risks associated with consuming food crops contaminated with metals and metalloids in a crude oil-impacted area of the Niger Delta, Nigeria. A total of 48 composite samples (12 each of yam, cassava, cocoyam, and waterleaf) were collected from the Ibaa community and its Right-of-Way (ROW) zone. Edible portions were acid-digested (HNO₃/HClO₄, 3:1) and analyzed for As, Pb, Cd, Cu, and Zn using Graphite Furnace Atomic Absorption Spectrophotometry (GF-AAS; Hitachi Z-2000, Tokyo, Japan). Quality assurance included reagent blanks, certified reference materials, and spike recoveries, with recoveries of 92-107%, RSD -1 mg/kg/day), Cu (1.0 × 10-1), and As (9.5 × 10-5) in cocoyam. Target Hazard Quotients (THQ) for Zn and Cu in children exceeded unity, and the Hazard Index (HI) peaked at 5.5 for cocoyam, surpassing the USEPA safety threshold (HI > 1). Total Lifetime Cancer Risk (TLCR) for As reached 1.5 × 10-4, exceeding the acceptable limit (1 × 10-4). These findings demonstrate significant non-carcinogenic and carcinogenic health risks, particularly for children consuming food crops from petroleum-exposed soils. Enhanced regulatory oversight, phytoremediation, and continuous biomonitoring are strongly recommended to mitigate dietary exposure in oil-impacted communities.