Elemental composition of cereal grains and the contribution to the dietary intake in the Nigerian population

Cereal grains occupy a sizable portion of the human diet and nutrition. This study quantified the concentrations of essential (Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, V, and Zn) and non-essential (As, Cd, Pb, and Hg) elements in cereal grains [Guinea corn, maize, wheat, and millet (pearl and finger)] from Jos market, Nigeria to ascertain their nutritional status and safety. Total mercury (THg) was determined by AAS and other elements by ICP-OES. Of all analyzed samples, the highest elemental concentrations (mg/kg dry weight) were As (1.70); Ca (3570); Cd (0.001); Co (0.97); Cr (6.24); Cu (20.0); Fe (709); K (5100); Mg (1450); Mn (477); Mo (2.10); Na (32.5); Ni (3.55); P (3500); Pb (2.48); V (1.72); THg (0.011); and Zn (37.5). The daily intakes (e.g., Cu, V, and Zn) and the weekly intakes (e.g., Cd, Ni, Pb, and Hg) were below the permissible limits. The hazard index (HI) values (i.e., HI <= 1.0) posed no hazard to adult consumers, but the cumulative cancer risk due to Cr, Ni, As, and Pb exceeded the benchmark (10-5). Health risk indices above the acceptable limits highlight the importance of more toxicological studies on cereal grains for public safety.