Concentrations of potentially toxic and essential trace elements in marketed rice of Bangladesh: Exposure and health risks

Abstract

Rice is a major dietary source of essential trace elements required for the human body but also can be an exposure pathway to different potentially toxic trace elements. This study determined various essential and toxic trace elements in rice from Bangladeshi markets and their possible health risks. Concentrations of essential and toxic trace elements in rice varied significantly from location to location. Mean concentrations (mg kg−1 as dry weight) of essential trace elements were found in the following order - Zn>Mn>Cu>Fe>Mo>Se>Co - and were within their maximum allowable limits. The average concentrations (mg kg−1) of toxic trace elements were as follows: As: 0.17, Cr: 0.18, Ni: 0.55 and Pb: 0.18, while 7% and 40% of the rice samples surpassed, respectively, the EU recommended limits of As and Pb. This study revealed that rice could be a primary exposure pathway of toxic elements, leading to either noncarcinogenic or carcinogenic health problems for daily rice consumers. The non-carcinogenic health risk was mainly associated with As which contributed 77% to the hazard index. The carcinogenic risk measured as incremental lifetime cancer risk (ILCR) was high (>10−4) with As, Cr and Ni, while Pb showed a moderate (<10−4) carcinogenic risk to adults. Rice can substantially be contaminated by trace elements other than As with potential human health risks. Consequently, regular monitoring of the marketed rice grain is demanded, backed up by viable mitigation strategies for reducing toxic elements uptake by rice grains.