Health risk assessment of some heavy metals in twenty one wheat products sold in Nigeria

Abstract

This study assessed some heavy metals in twenty one wheat products originating from Nigeria and six other countries sold in local markets in Ijebu-Ode, Ibadan and Lagos cities in Nigeria and their possible health risks were also evaluated. Wheat-based food samples were digested and analyzed using Microwave Plasma coupled Atomic Emission Spectrometry (MP-AES) technique. The heavy metal contents in local and foreign wheat products ranged as follows: As (0.014-0.033 mg.kg^-1), Cd (0.067-0.330 mg.kg^-1), Ni (-0.002-0.104 mg.kg^-1) and Pb (0.166-0.655 mg.kg^-1). The mean contents of Cd and Pb exceeded the acceptable thresholds set by FAO/WHO while those of As and Ni were below permissible limits recommended by FAO/WHO. The health hazard indices for the four heavy metals, reported as follows: Ni (0.005), As (0.201), Pb (0.211), and Cd (0.490), fall within the low hazard range except for Ni whose hazard index could be regarded as negligible. The health hazard risk, which may be posed by each metal, occurred in a sequence of HQ (Ni) < HQ (As) < HQ (Cd) < HQ (Pb) <1, with each occurring within the safe limit set by the United States Environmental Protection Agency (USEPA). The combined non-carcinogenic risk of the four heavy metals (ΣHQ = 0.906) occurred at the low-risk index. The carcinogenic risk index was below 1x 10-4 threshold recommended by USEPA, which indicates that the combined concentrations of the four metals possess a weak potential to modulate lifelong carcinogenic ailments for consumers of such wheat products.