@article{lineberger_badruzzaman_ali_polizzotto_2013, title={Arsenic Removal from Flowing Irrigation Water in Bangladesh: Impacts of Channel Properties}, volume={42}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2013.05.0191}, abstractNote={Across Bangladesh, dry-season irrigation with arsenic-contaminated well water is loading arsenic onto rice paddies, leading to increased arsenic concentrations in plants, diminished crop yields, and increased human health risks. As irrigation water flows through conveyance channels between wells and rice fields, arsenic concentrations change over space and time, indicating that channels may provide a location for removing arsenic from solution. However, few studies have systematically evaluated the processes controlling arsenic concentrations in irrigation channels, limiting the ability to manipulate these systems and enhance arsenic removal from solution. The central goal of this study was to quantify how channel design affected removal of dissolved arsenic from flowing irrigation water. Field experiments were conducted in Bangladesh using a chemically constant source of arsenic-contaminated irrigation water and an array of constructed channels with varying geometries. The resulting hydraulic conditions affected the quantity of arsenic removed from solution within the channels by promoting known hydrogeochemical processes. Channels three times the width of control channels removed ∼3 times the mass of arsenic over 32 min of flowing conditions, whereas negligible arsenic removal was observed in tarp-lined channels, which prevented soil-water contact. Arsenic removal from solution was ∼7 times higher in a winding, 200-m-long channel than in the straight, 45-m-long control channels. Arsenic concentrations were governed by oxidative iron-arsenic coprecipitation within the water column, sorption to soils, and phosphate competition. Collectively, these results suggest that better design and management of irrigation channels may play a part in arsenic mitigation strategies for rice fields in Southern Asia.}, number={6}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Lineberger, Ethan M. and Badruzzaman, A. Borhan M. and Ali, M. Ashraf and Polizzotto, Matthew L.}, year={2013}, pages={1733–1742} }
 @article{polizzotto_lineberger_matteson_neumann_badruzzaman_ali_2013, title={Arsenic transport in irrigation water across rice-field soils in Bangladesh}, volume={179}, ISSN={["0269-7491"]}, DOI={10.1016/j.envpol.2013.04.025}, abstractNote={Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes.}, journal={ENVIRONMENTAL POLLUTION}, author={Polizzotto, Matthew L. and Lineberger, Ethan M. and Matteson, Audrey R. and Neumann, Rebecca B. and Badruzzaman, A. Borhan M. and Ali, M. Ashraf}, year={2013}, month={Aug}, pages={210–217} }