Arsenic contamination in the food chain and its risk assessment of populations residing in the Mekong River basin of Cambodia.

In the present study, we investigated the potential arsenic exposure of Cambodian residents from their daily food consumption. Environmental and ecological samples such as paddy soils, paddy rice (unhusked), staple rice (uncooked and cooked), fish and vegetables were collected from Kandal, Kratie and Kampong Cham provinces in the Mekong River basin of Cambodia. After acid-digestion, digestates were chemically analyzed by inductively coupled plasma mass spectrometry. Results revealed that the means of total arsenic concentration ([As]tot) in paddy soils and paddy rice from Kandal were significantly higher than those from Kampong Cham province (t-test, p<0.05). Moreover, a significant positive correlation between the [As]tot in paddy soils and paddy rice was found (r(14) = 0.826, p<0.01). Calculations of arsenic intake from food consumption indicated that the upper end of the range of the daily dose of inorganic arsenic for Kandal residents (0.089-8.386 μg d(-1) kg(-1) body wt.) was greater than the lower limits on the benchmark dose for a 0.5% increased incidence of lung cancer (BMDL0.5 is equal to 3.0 μg d(-1) kg(-1) body wt.). The present study suggests that the residents in Kandal are at risk of arsenic intake from their daily food consumption. However, the residents in Kratie and Kampong Cham provinces are less likely to be exposed to arsenic through their daily dietary intake. To the best of our knowledge, this is the first report estimating the daily intake and daily dose of inorganic arsenic from food consumption in the Mekong River basin of Cambodia.