Toxicological Risk Associated with Consumption of Rice Sold in Uganda

Previous studies have reported the presence of aflatoxins (AFB1, AFB2, AFG1 and AFG2), heavy metals (As, Cd and Pb) and organochlorine pesticide residues (OCPs) in rice sold in Uganda. However, the potential health effects associated with consumption of rice have not been evaluated. The aim of this study was to evaluate the health risk of consuming rice sold in Uganda. A total of 45 packed and 30 open traded rice samples were randomly collected from retail outlets in the main rice trading areas of Uganda. Rice was analysed for AFB1, AFB2, AFG1 and AFG2, As, Cd, Pb and OCPs using AOAC standard methods. Dietary exposure of the consumers to contaminants was assessed using the estimated daily intake (EDI). The Hazard index (HI) and the incremental lifetime cancer risk (ILCR) were determined to define the non-carcinogenic and carcinogenic risk from contaminants, respectively. The potency of liver cancer cases in Uganda was 1.02E-5 and 1.05E-5 adults/year/100,000, and 6.50E-4 and 6.72E-5 infants /year/100,000 for open traded and packed rice, respectively. The values obtained for the ILCR for Arsenic detected in rice were 1.14E-2 and 7.28E-2 for adults and infants, respectively. The ILCR of all detected OCPs in adults and infants were higher than 1.0E-4, in both open traded and packed rice. This study established a potential carcinogenic risk from consumption of rice sold in Uganda in both infants and adults at the current level of contamination and consumption rate. Establishment of a monitoring system along the entire rice value chain; enforced by a national regulatory body can provide timely feedback on the levels of contamination and the progress in reducing the contamination burden.