Determination of Iron Species in Iron-Enriched Compost used to Attenuate Arsenic in Contaminated Soil
EMSL Project ID
50724
Abstract
Up to the mid 1900’s, hundreds of thousands of acres across the United States were repeatedly treated with lead-arsenate pesticides to prevent the decimation of orchards by codling moths. Metal arsenate pesticides were eventually phased out starting in 1947 and, in the decades following, much of the historically treated land was sold for housing and development. As a biologically harmful element, arsenic (As) exposed to humans in these regions is high, facilitated through dust inhalation, soil ingestion, and plant uptake. Here, we assess compost enriched with iron (Fe) as a cost-effective and feasible remediation tool to reduce human exposure. Previous research has shown that high Fe-biosolids can reduce bioavailable soil As by providing sorption sites that include Fe- (hydr)oxide particles and ternary complexes with organic FeOH functional groups. Similarly, in our study, we determine the fate or speciation of Fe-amendments used to enrich compost sourced from two different Fe-salts, and how the species of Fe influences the adsorption, retention, and stability of As. Our goal at EMSL is to Aim 1) determine if the Fe-speciation using Mossbauer spectroscopy is comparable to Fe values derived from single extraction Fe-fractionation, and; Aim 2) gain greater incite as to why we’re seeing As-adsorption differences with the different treatments. Previous Mossbauer analysis was already conducted on two samples, and the ratios compared to the wet chemical single Fe-extracts. The comparisons showed remarkable similarities between the two approaches but required at least two more samples analyzed in a similar fashion to get a more complete picture. Therefore, we propose using the same Mossbauer spectroscopy analysis on two more Fe-enriched compost samples which would ultimately result in acquiring spectra for low and high-Fe concentrations for two different Fe-salts. This would allow us to not only confirm the single-extraction values for a range of Fe-enriched compost, but would also give us a comprehensive characterization of As adsorption properties on a biologically active, Fe-enriched carbon media.
Project Details
Project type
Limited Scope
Start Date
2019-03-01
End Date
2019-05-01
Status
Closed
Released Data Link
Team
Principal Investigator