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.