Field Screening for Low Levels of Toxic Inorganic Arsenic in Dry-Season Rice Varieties from Bangladesh

Abstract

Rice varieties with low arsenic content (As) could address some aspects of human health risks linked to As-tainted rice consumption. This study evaluated 46 rice cultivars from Bangladesh for their total and speciated As (inorganic and organic) in grains. The rice varieties were cultivated under a continuously flooded irrigation system with As-tainted groundwater. The study revealed notable varietal effects on total and speciated As concentrations. The levels of total As in unpolished rice ranged from 219 to 562 μg kg–1 among different rice cultivars, with BRRI dhan47 exhibiting the lowest and BR7 showing the highest concentrations. In brown rice, inorganic As was the dominant form, contributing 54–91% of total As. Nevertheless, a 10% polishing process can significantly diminish the levels of total As (14–39%), inorganic As (12–46%), and DMA (12–36%) found in brown rice. Grain As revealed a negative relationship between the rice grain yield and some beneficial micronutrients. Based on grain As levels, a couple of low As accumulating rice varieties have been identified, which could be promoted to grow in As-prone areas as a low-cost mitigation strategy. Consequently, screening low-accumulation rice cultivars could minimize the As load in humans, which occurs through rice consumption in As-endemic areas.