|Maguffin, Scott - Cornell University - New York|
|Derry, Louis - Cornell University - New York|
|Huang, Rong - Cornell University - New York|
|Reid, Matthew - Cornell University - New York|
Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 12/10/2017
Publication Date: 12/11/2017
Citation: Maguffin, S.C., McClung, A.M., Rohila, J.S., Derry, L., Huang, R., Reid, M.C. 2017. Microbial-driven arsenic cycling in rice paddies amended with monosodium methanearsonate. American Geophysical Union. Hydrology and Biogeochemical Cycling at American Geophysical Union (AGU) 2017 Fall Meeting, December 11-15, 2017, New Orleans, Louisiana.
Technical Abstract: Rice consumption is the second largest contributor to human arsenic exposure worldwide and is linked to many serious diseases. Because rice is uniquely adapted for agricultural production under flooded soils, arsenic species solubilized in such environments can be effectively transported into plant tissue via root transporters. Through this process, both inorganic and organic (methylated) arsenic species can accumulate to problematic concentrations and may affect grain yield as well as crop value. The distribution of these species in plant tissue is determined by arsenic sources as well as enzymatic redox and methylation-demethylation reactions in soils and pore water. Historic use of organoarsenic-based pesticides in US agriculture may provide an enduring source of arsenic in rice paddies. However, it is unclear how persistent these organic species are in the adsorbed phase or how available they remain to rice cultivars throughout the growing season. To investigate, we conducted a field experiment in a 2x2 factorial design examining the effects of irrigation methods (continuous flooding and alternate wetting and drying) and monosodium methanearsonate (MSMA) application on the abundance and speciation of arsenic in pore water, soil solid phases, and rice plant tissues. We monitored arsenic speciation and partitioning between these reservoirs at semi-weekly to semi-monthly frequencies. Pore water arsenic speciation was determined using LC-ICP-MS, and X-ray absorption near-edge structure (XANES) analysis was employed to speciate the arsenic within solid-phase soil and plant tissue throughout the growing season. These data help clarify the role of two irrigation methods and MSMA amendments for arsenic bioavailability and speciation in rice. Further the study will also illuminate the significance of microbial metabolism in the reapportionment of arsenic within the soil-plant-water system and its impact on arsenic levels in rice grains.