Dietary intake and risk assessment of heavy metals from selected biscuit brands in Nigeria

Abstract

Biscuits are commonly consumed by all age groups particularly children in Nigeria. However, this food item may be contaminated with heavy metals picked up from the ingredients, production and packaging methods. Therefore, this study assessed the concentrations of heavy metals in biscuits and its associated health risk status. In the light of this, concentrations of seven metals (Mn, Zn, Cu, Cr, Fe, Pb and Cd) in ten selected brands of biscuits available in the Nigerian market were assessed in this study. Health risk assessment and dietary exposure to heavy metals were also estimated in view of presenting information on the dietary intakes of heavy metals and the lifetime adverse health effects related with the consumption of these food products. The metal concentrations were determined by Flame Atomic Absorption Spectrophotometer after acid digestion of the samples. The observed mean concentrations of trace metals were ND-12.5 mg/kg Mn, 5.64-157 mg/kg Zn, ND-46.4 mg/kg Cr, 99.4-296 mg/kg Fe, 3.11-92.0 mg/kg Pb. Cu and Cd were not detected in all the biscuit samples. From the analysis of heavy metals, it was observed that Cr and Pb were higher than Food and Agricultural Organization/ World Health Organization (FAO/WHO) safe limit for cereals and cereal-based food products. The estimated dietary daily intake values of Cr and Pb surpassed their permissible intake limits, while the intakes of beneficial nutritive metals, such as Zn and Fe, from the ingestion of these food products were quite low and contributed insignificantly to the dietary requirements of Zn and Fe. The overall estimated target hazard quotient (ƩTHQ) values for the heavy metals were high suggesting possible health concern for infants, school children and adults who consume these products consistently on a daily basis over a long period of time.