Dietary Exposure to Heavy Metal Contaminated Rice and Health Risk to the Population of Monrovia

Abstract

The aim of this study was to assess the exposure of the population of Monrovia to Heavy metals (Arsenic, Cadmium, Chromium, Lead, Mercury and Nickel) through the consumption of rice and the health risk posed. A total of forty one (41) imported and nineteen (19) locally cultivated rice samples were collected from major markets in Monrovia. A mixture of nitric, per chloric and sulfuric acids were used for complete digestion of the samples and the levels of the metals were determined using ICP-MS and AAS techniques. Dietary exposure of the consumers to the metals was assessed by comparing the Estimated Daily Intake (EDI) to the Provisional Tolerable Daily Intake (PTDI) of the metals, and the potential non-carcinogenic health risk was assessed using Hazard Quotients and Hazard Indices. Carcinogenic health risk from Arsenic was assessed by using Incremental Lifetime Cancer Risk values. Incremental Lifetime Cancer Risk values were less than the US EPA threshold value of 1.00E-04. Hazard Quotients and Hazard Indices for all the metals were less than US EPA permissible value of 1; suggesting that the consumption of the products constitute no potential individual or combined health risk to the population with regards to the tested metals. Although the current levels of heavy metals in the products are negligible, regular monitoring of contaminant levels is highly recommended.