|Maguffin, Scott - Cornell University - New York|
|Reid, Matthew - Cornell University - New York|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2018
Publication Date: 7/6/2018
Citation: Maguffin, S.C., Reid, M.C., Mcclung, A.M., Rohila, J.S. 2018. Methylated arsenic cycling in rice paddies under varied irrigation methods. Meeting Abstract. July 1-6, 2018.
Technical Abstract: Rice consumption is the second largest contributor to human arsenic (As) exposure worldwide, and is linked to many serious diseases in humans. Rice cultivars can effectively transport As into various plant tissues via root transporters under conventional flooded cultivation. Historic use of organo-arsenic 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 cropping season. We conducted a field experiment in a 2x2 factorial design examining the effects of irrigation methods and monosodium methanearsonate (MSMA) application on the abundance and speciation of As in pore-water, soil, and rice plant tissues throughout a growing season. This presentation will be focused on the distribution of As species, as well as enzymatic redox and methylation-demethylation reactions in soils and pore-water that determine the fate and transport of As species in plant tissue. Soil was collected using a soil probe and preserved anaerobically in heat sealed mylar bags flushed with research grade argon gas. Soil samples were analyzed for X-ray absorption near-edge structure (XANES) using Cornell University’s High Energy Synchrotron Source (CHESS). Data from the As analyses, combined with pore water and solid phase chemistry, provide a detailed characterization of arsenic redox chemistry in rice paddy soils as a function of irrigation controls and background arsenic concentrations. Results demonstrated significant differences in As speciation among irrigation treatments.