Modeling dietary intake of arsenic and the associated human health risk for people living in rural Bangladesh

Dietary intake of Arsenic (As) via contaminated drinking water and food is the major exposure pathway for people living in rural Bangladesh and causes adverse human health effects where groundwater As contamination and the associated human health risks are potentially spatially connected. This research quantifies the spatial variability of As in the rural landscape in relation to As concentrations in drinking water, rice and other foods. The impact of As exposure on an individual's human health was quantified using the average daily intake (ADI) to calculate the Hazard Quotient (HQ) and Cancer Risk (CR) using Bangladesh specific parameters via integration of a number of complex databases using SQL queries and spatial modeling. The As concentration in tubewell water ranged from 0 to 808 μg L^-1 with a mean of 48 μg L^-1 indicating that a large proportion of the population (73%) were exposed daily to >10 μg L^-1 As via drinking water. Arsenic concentrations were highly spatially variable even for water sources located within close proximity (< 50 m). A typical adult Bangladeshi diet consisted of a large volume of water (2.6 ± 1.4 L day^-1), together with a large portion of rice (1494 ± 776 g FW day^-1), vegetables (136 ± 37g FW day^-1) and dal (35 ± 2 g FW day^-1), supplemented by irregular consumption of small amounts of fish or meat. Dietary pattern analysis indicated that, the rural diet was primarily reliant on water (53%) and cooked rice (31%) supplemented by smaller amounts of vegetables (3%), dal (1%), fish (1.5%), meat (1.5%) and other foods (9%). The ADI of As was 1.98 μg kg^-1 BW day^-1 (n=345), and both HQ and CR were significantly higher than acceptable risk levels.