Heavy metals, macro-minerals and human health risk assessment of spiced and unspiced tiger nut drink commercialized in Port Harcourt, Rivers State, Nigeria

Abstract

The need for cheap, nutritional, refreshing and local content development has increased the demand and consumption of Tiger nut drink by residents of Port Harcourt and its environs in recent years. However, the inadequate nutritional information and without nutritional facts label has made it difficult for the Tiger nut consuming populace to ascertain its health benefits. Hence, the objective of this paper was to investigate the concentrations of selected heavy metals (Pb, Ni, Fe, Cu, and Zn), macro-minerals (Mg and Ca) and human health risk assessment of spiced and unspiced Tiger nut drink commercialized in Port Harcourt, Rivers State, Nigeria using standard analytical techniques after mixed acid digestion. The mineral elements were found in the order of Mg (79.87 mg/L) > Ca (50.79 mg/L) and Mg (96.82 mg/L) > Ca (68.18 mg/L) in unspiced and spiced tiger nut drinks respectively [< WHO: Mg (150 mg/L), Ca (200 mg/L)] while heavy metals concentrations in the samples analyzed were Fe (1.82 mg/L) > Zn (1.16 mg/L) > Cu (0.4160 mg/L) and Fe (2.12 mg/L) > Zn (1.51 mg/L) > Cu (0.45 mg/L) in unspiced and spiced tiger nut drinks respectively. Pb and Ni were undetected (< 0.00 mg/l) in both unspiced and spiced gingered tiger nut drinks studied. Only Fe and Cu concentrations exceeded WHO standards (0.3 and 0.02 mg/L). However, intake of these heavy metals is unlikely to pose any non-carcinogenic health risk to consumers (target hazard quotient (THQ) < 1, HI<1 for adults and children) in both spiced and unspiced tiger nut drink. Generally, results from this study showed higher concentrations of metals in spiced tigernut drink than in the unspiced tiger nut drink. This could be attributed to the combined bioaccumulated levels of heavy metals in the tiger nut tubers and in the spice used. Frequent consumption of spiced tiger nut drink may rapidly increase the levels of heavy metals in the human body and pose chronic risk to human health and also beneficially increase the levels of macrominerals in the body. Standard production processes and regulated spicing of tiger nut drink needs to be provided by regulatory agencies (NAFDAC) and made available to producers of tiger nut drink.