Arsenic levels in rice brands sold in Kampala: an experimental study to show the modifying effect of boiling, soaking and washing

Abstract

Arsenic is an important environmental pollutant with potential cancer-causing effects. It contributes to acute and chronic toxicity depending on the doses or duration of exposure. In this study, we estimated the concentration of total arsenic in different rice brands sold in Uganda, where rice is a staple food. We conducted an experimental study. Different rice brands were obtained from supermarkets and grocery shops, and assessed for arsenic using atomic absorption spectrometry. The concentrations of arsenic in rice were estimated after boiling, washing, or overnight soaking in plenty of water to see if these methods reduce arsenic levels efficiently in food. The concentrations of arsenic in the different rice brands were compared using an unpaired t-test after setting a p-value of ≤0.05 as significant. The G-rice brand had the lowest arsenic levels of 1.4±0.0002 ppm and the C-rice brand had the highest levels of 2.4±0.004 ppm. The tap water used to boil, soak and wash the rice brands had much higher arsenic levels of 3.5±0.000003 ppm, leading to increased retention of the heavy metal in the rice. Rice brands sold in Kampala city seem to have higher than acceptable arsenic levels. Increased vigilance in terms of routine monitoring for the levels of arsenic in rice and water used during food preparation by the Ugandan food or water safety regulatory authorities is highly recommended.