Superfund Research Program

Enhanced Remediation at U.S. Arsenic-Contaminated Sites

Project Leader: Benjamin C. Bostick
Co-Investigator: Steven N. Chillrud
Grant Number: P42ES010349
Funding Period: 2000-2021

Project-Specific Links

Final Progress Reports

Year:   2020  2016  2010  2005 

Arsenic (As) groundwater contamination is a challenge to remediate at Superfund Sites. The research team on this project is developing magnetite-based strategies as a new in situ remediation strategy. In the last year, researchers have begun to (1) to scale up their initial bench-scale experiments examining As contamination; (2) to document the formation of magnetite, and the extent of As removal from groundwater, in open systems (columns) using sediments from the Dover (NH) Superfund site (Sun et al., 2016). Nanoparticulate magnetite forms a diffuse reactive barrier in columns that effectively removes As as groundwater flows through it. (3) The research team is currently parameterizing a biogeochemical model that links the biological processes to mineral transformations and As retention, and scales them up (Sun et al.). Finally (4) a mechanism of magnetite formation and better design groundwater remediation strategies has started to be established (Jamieson et. al). These results indicate that autotrophic iron(II) oxidizers are key to producing magnetite under groundwater conditions typical of As contamination, and that these organisms can be stimulated most effectively by carefully controlling the ratio between iron(II) and nitrate concentrations. Investigators are beginning to design field trials for nitrate-Fe(II) injections in the Lot 84 Superfund Site (Raleigh, NC) and expect the results to be the first direct field-scale test of this method.