title: Diffusional losses of amended anaerobic electron acceptors in sediment field microcosms.
abstract: Hudson River sediment microcosms from Piles Creek (PC), Piermont Marsh (PM), and Iona Island (II) were amended with approximately 100mM nitrate or sulfate to stimulate anaerobic bioremediation. Nitrate and sulfate decreased over two years of field incubation and the fraction of these losses due to diffusion to the water column was predicted using Fick's law. Apparent diffusion (D(app)) values of 1-4x10(-10)m(2)s(-1) predicted the majority of loss/gain from/to the sediments by 700 d, but not at all times. Effective diffusion (D(eff)) values predicted by the porosity function (D(eff)=D(mol)epsilon(4/3)) were larger than those observed in the field, and field data indicates a cube power relationship: D(eff)=D(mol)epsilon(3). D(app) greatly increased in surficial layers at PM and PC in year two, suggesting that bioadvection caused by bioturbating organisms had occurred. The effects of bioturbation on transport to/from the sediments are modeled, and results can be applied to various sediment treatment scenarios such as capping.
authors.affiliation: Center for Experimental Study of Subsurface Environmental Processes (CESEP), Environmental Science and Engineering Division, Colorado School of Mines, Golden, CO, United States. mittal.menka@gmail.com
authors.forename: Menka
authors.initials: M
authors.lastname: Mittal
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Rockne
mesh_terms: D000693:Anaerobiosis; D017753:Ecosystem; D004583:Electrons; D052918:Environmental Restoration and Remediation / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D008956:Models, Chemical; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D014873:Water Pollutants