Groundwater Irrigation and Arsenic Speciation in Rice in Cambodia

Date
2018-07
Authors
Murphy, Tom
Phan, Kongkea
Yumvihoze, Emmanuel
Irvine, Kim
Wilson, Kenneth
Lean, David
Ty, Borey
Poulain, Alexander
Laird, Brian
Chan, Laurie Hing Man
Journal Title
Journal ISSN
Volume Title
Publisher
Pure Earth
Abstract
Background: Arsenic bioaccumulation in rice is a global concern affecting food security and public health. Objective: The present study examined arsenic species in rice in Cambodia to characterize health risks with rice consumption and to clarify uncertainties with Codex guidelines. Methods: The present study collected 61 well water samples, 105 rice samples, 70 soil samples, and conducted interviews with 44 families in Preak Russey near the Bassac River and Kandal Province along the Mekong River in Cambodia. Analyses of metals, total arsenic and arsenic species were conducted in laboratories in Canada, Cambodia and Singapore. Results: Unlike in Bangladesh, rice with the highest total arsenic concentrations in Cambodia contains mostly organic arsenic, dimethylarsinic acid (DMA), which is unregulated and much less toxic than inorganic arsenic. The present study found that storing surface runoff in ditches prior to irrigation can significantly reduce the arsenic concentration in rice. It is possible to remove > 95% of arsenic from groundwater prior to irrigation with natural reactions. Conclusions: The provision of high quality drinking water in 2015 to Preak Russey removed about 95% of the dietary inorganic arsenic exposure. The extremes in arsenic toxicity that are still obvious in these farmers should become less common. Rice from the site with the highest documented levels of arsenic in soils and water in Cambodia passes current Codex guidelines for arsenic.
Description
Keywords
bioaccumulation, dimethylarsinic acid, irrigation, remediation, rice, arsenic, Biology
Citation
Murphy, T., Phan, K., Yumvihoze, E., Irvine, K., Wilson, K., Lean, D., Ty, B., Poulain, A., Laird, B., & Chan, L. H. M. (2018). Groundwater irrigation and arsenic speciation in rice in Cambodia. Journal of Health and Pollution, 8(19), pp. 1-9.