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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/12101

Title: Health Risk from Heavy Metals to the Population of Monrovia, Liberia through the Consumption of Rice
Authors: Gomah, Galileo Lenn
Issue Date: 27-Apr-2020
Abstract: Rice is the major component of Liberian diets. It is the most widely consumed crop in Monrovia. Environmental pollution can possibly contaminate the crop with heavy metals. In this study, sixty one rice samples comprising nine domestic cultivated and twenty imported brands of different batches were obtained from six local markets in Monrovia, Liberia and evaluated for the concentrations of six heavy metals: Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb), Mercury (Hg) and Nickel (Ni). The level of Hg concentrations was determined by AAS using a Lumex RA-915M Portable Zeeman Automatic Mercury Analyzer while the levels of As, Cd, Cr, Pb and Ni concentrations were determined by ICP-MS using an Agilent 7900 Inductively Coupled Plasma Mass Spectrometer. The concentrations of As, Cd, Cr, Pb, Hg and Ni ranged from 0.0011 to 0.0181, 0.0048 to 0.1179, 0.050 to 0.4245, 0.0011 to 0.0371, 0.0011 to 0.0094 and 0.0151 to 0.6552 mg/kg respectively. The study revealed no significant statistical difference in the level of the metal concentrations between the locally cultivated and imported rice samples, except for As (P = 0.002). Dietary exposure of the consumers to the metals was assessed by comparing Estimated Daily Intake to the Provisional Tolerable Daily Intake of the metals, and the non-carcinogenic health risk posed was assessed using Hazard Quotients and Hazard Indices. Carcinogenic health risk posed from Arsenic was assessed by using Incremental Lifetime Cancer Risk values. Incremental Lifetime Cancer Risk for As was less than the US EPA threshold value of 10-4. Hazard Quotients and Hazard Indices for all the metals were less than the US EPA permissible value of 1. Therefore, consuming the selected rice samples sold on the local markets in Monrovia at the current consumption rate posed no health risk to the population from As, Cd, Cr, Pb, Hg and Ni alone or when combined. Hence, there is no need for consumption advisory. However, regular monitoring of contaminant levels is highly recommended.
Description: A Thesis Submitted to the Department of Chemistry, College of Science in Partial Fulfilment of the Requirements for a Degree of: MASTER OF PHILOSOPHY (ENVIRONMENTAL CHEMISTRY) May, 2018
URI: http://hdl.handle.net/123456789/12101
Appears in Collections:College of Science

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