Geographical variation and age-related dietary exposure to arsenic in rice from Bangladesh.

An extensive number (965) of rice samples collected by household survey from 73 upazilas (i.e. sub-districts) in Bangladesh was analyzed to determine regional variation, distribution and associated health risks from arsenic (As). No previous study had conducted a study examining such a large number of rice samples. The mean and median concentrations of total As were 126μg/kg and 107μg/kg, respectively, ranging from between 3 and 680μg/kg. Importantly, total As levels of aromatic rice were significantly lower (average 58μg/kg) than non-aromatic rice (average 150μg/kg) and also varied with rice grain size. The variation in As content was dominated by the location (47% among the upazilas, 71% among districts) and rice variety (14%). Inorganic As content in rice grain ranged between 11 and 502μg/kg (n=162) with the highest fraction being 98.6%. The daily intake of inorganic As from rice ranged between 0.38 and 1.92μg/kg BW in different districts. The incremental lifetime cancer risk (ILCR) for individuals due to the consumption of rice varied between 0.57×10-3 to 2.88×10-3 in different districts, and 0.54×10-3 to 2.12×10-3 in different varieties, higher than the US EPA threshold. The 2-10 age group experiences higher carcinogenic risks than others and females are more susceptible than males.