Arsenic in rice grown in low-arsenic environments in Bangladesh

It has previously been reported that rice grown in regions of Bangladesh with low-arsenic (As) concentrations in irrigation water can have relatively high concentrations of As within their grains. This study aims to determine how widespread this issue is, and determine the seasonal variation in grain As in these regions. Levels of As were measured in shallow tube well (STW) water, soils, and rice grains collected during the Boro (dry) and Aman (wet) seasons from six Upazilas (sub-districts) of Bangladesh where As levels in groundwater were known to be low. In all the Upazilas, the As concentrations in STW water were <50 μg L−1. The As levels in soil samples collected from the Upazilas ranged between 0.2–4.0 mg kg−1 in the samples collected during the Boro season, and 0.4–5.7 mg kg−1 in the samples collected in the Aman season. Levels of As in both Boro and Aman rice grain varied widely: in Boro 0.02–0.45 mg kg−1, and in Aman 0.01–0.29 mg kg−1. Additionally, a household survey of dietary habits was also conducted in one Upazila by estimating As ingestion by 15 head female members. On average, the women consumed 3.1 L of water, 1.1 kg of cooked rice, and 42 g dry weight of curry per day. The total As ingestion rates ranged from 31.1–129.3 μg day−1 (mean 63.5 μg kg−1). These findings indicate that the major route of As ingestion in low groundwater-As areas of Bangladesh is rice, followed by curry and then water.