title: Arsenic transport in irrigation water across rice-field soils in Bangladesh.
abstract: 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.
authors.affiliation: Department of Soil Science, North Carolina State University, 101 Derieux St, Campus Box 7619, Raleigh, NC 26795, USA. matt_polizzotto@ncsu.edu
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Polizzotto
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Lineberger
authors.forename: Audrey R
authors.initials: AR
authors.lastname: Matteson
authors.forename: Rebecca B
authors.initials: RB
authors.lastname: Neumann
authors.forename: A Borhan M
authors.initials: AB
authors.lastname: Badruzzaman
authors.forename: M
authors.initials: M
authors.lastname: Ashraf Ali
mesh_terms: D057914:Agricultural Irrigation; D001151:Arsenic / Q000032:analysis*; D001459:Bangladesh; D005506:Food Contamination; D012275:Oryza; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D001151:Arsenic