Spatial and Temporal Variability of Arsenic Solid-State Speciation in Historically Lead Arsenate Contaminated Soils

Journal Article · Sun Jan 01 04:00:00 EST 2006 · Environ. Sci. Tech.

DOI:https://doi.org/10.1021/es051266e· OSTI ID:914296

Arai, Y; Lanzirotti, A; Sutton, S; Newville, M; Dyer, J; Sparks, D

The arsenic (As) solid-state speciation (i.e., oxidation state, precipitates, and adsorption complexes) is one of the most important factors controlling dissolved As concentrations at As contaminated sites. In this case study, two representative subsurface samples (i.e., oxidized and semi-reduced sites) from former lead arsenate contaminated soils in the northeastern United States were chosen to investigate the effects of aging on As retention mechanisms using multiscale spectroscopic techniques. X-ray powder diffraction (XRD), synchrotron based microfocused ({micro}) XRD, in situ {micro}-synchrotron based X-ray fluorescence spectroscopy (SXRF), and {micro}-X-ray absorption near edge structure (XANES) spectroscopy were used to compliment the final bulk X-ray absorption spectroscopy (XAS) analyses. In the sample from an oxic area, As is predominantly ({approx}71%) present as As(V) adsorbed onto amorphous iron oxyhydroxides with a residue ({approx}29%) of an original contaminant, schultenite (PbHAsO{sub 4}). Contrarily, there is no trace of schultenite in the sample from a semi-reduced area. Approximately 25% of the total As is present as adsorbed phases on amorphous iron oxyhydroxide and amorphous orpiment (As{sub 2}S{sub 3}). The rest of the fractions ({approx}46%) were identified as As(V)-Ca coprecipitates. This study shows that aging effects can significantly alter the original chemical constituent (schultenite) in soils, resulting in multi and site-specific As solid-state speciation. The variability in spatial and temporal scale may be important in assessing the environmental risk and in developing in situ remediation technologies.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 914296
• Report Number(s): BNL--78864-2007-JA
• Journal Information: Environ. Sci. Tech., Journal Name: Environ. Sci. Tech. Journal Issue: 3 Vol. 40; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ABSORPTION
ABSORPTION SPECTROSCOPY
ADSORPTION
AGING
ARSENATES
ARSENIC
DIFFRACTION
FLUORESCENCE SPECTROSCOPY
IRON
RESIDUES
RETENTION
SOILS
SPECTROSCOPY
SYNCHROTRONS
national synchrotron light source