Assessment of Heavy Metal Contamination in Millet Seed Cultivated in Senegal: Implication for Human Health

Abstract

A sample of hulled millet and an unhulled millet sample were collected from a rural area and their metal contents (Na, K, Mg, Ca, Cr, Fe, Ni, Cu, Zn, Cd, and Pb) were analyzed. The samples were wetly digested, and the metals were analyzed by atomic absorption spectroscopy. The Na concentration was measured between 45.1 and 64.5 mg/kg in the hulled millet (I) and unhulled millet (II) samples. Potassium was detected at concentrations between 3500.9 and 4519.5 mg/kg in I and II, respectively. The Mg concentration was measured between 1250.4 and 1476.7 mg/kg in samples I and II. Calcium was found at low values ​​of 11.80 and 14.2 mg/kg in both I and II, respectively. Chromium, nickel and lead are completely absent in both millet samples. Iron concentrations in I and II are 14.9 and 16.9 mg/kg in I and II, respectively. Copper and zinc are between 0.9 mg/Kg (I) and 1.1 mg/Kg (II) for Cu and 14.2 mg/Kg (I) and 16.1 mg/Kg (II) for Zn. Cadmium is between 0.010 mg/kg and 0.020 mg/kg in samples I and II. According to this study, hulled millet has lower levels of all elements than unhulled millet, suggesting that the hull also contains metal. Since the Na/K ratio is less than 1, which is the recommended value, these millet samples could prevent high blood pressure. The Ca/Mg ratio, which deviates in both samples from the recommended value of between 1 and 2, is a handicap for consumption based mainly on millet grown in this rural area. According to the criteria recommended by the WHO and FAO, millet consumption in Senegal did not present an immediate health risk.