Concentrations and Human Health Risk Assessment of Cd, Co, Cr, Ni, and Pb via Eating White Granulated Garri Produced in Nigeria

Abstract

White granulated garri, an extensively consumed foodstuff in Nigeria made from fermented cassava tubers has recorded little studies on its heavy metals content. The concentrations of Cd, Co, Cr, Ni and Pb in commercial white granulated garri commonly sold in three major markets in Port Harcourt, Nigeria were established using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) after microwave-assisted acid digestion. The mean concentrations (x ±SD,in mg/kg on dry-weight basis) of heavy metals in garri samples were Cd: 0.021 ± 0.005, Co: 0.027 ± 0.004, Cr: 2.50 ± 0.047, Ni: 0.849 ± 0.021, and Pb: 0.522 ± 0.039 respectively. A food frequency questionnaire-based (FFQ) survey on dietary consumption rates of garri as a source of carbohydrate among consumers and marketers showed that garri accounted for ˃ 97.5% of total carbohydrate consumed in Nigeria. Statistical evaluation of the data by one-way analysis of variance discloses noteworthy differences of metal contents for Cd, Co, Ni and Pb in garri from the study area with the exception of Cr. The mean daily intake of metals (mg/person/day) from garri consumption using dietary modelling was found to be Cd: 1.49 x 10-4, Co: 1.34 x 10-5, Cr: 1.24 x 10-2, Ni: 4.23 x 10-3 and Pb: 2.60 x 10-3 respectively. These values are lower than the upper tolerable daily intake limits for heavy metals in food. The target hazard quotients (THQ), health risk index (HRI) and lifetime cancer risk (CR) for Cd, Co, Cr, Ni, and Pb indicate that, the probable human health risk associated with consumption of garri for the target population is moderately low at the moment. However, modest consumption rate of the product is recommended due to potential bioaccumulation of heavy metals found in garri.