[CPEO-BIF] Arsenic in California's Mother Lode

[Lenny Siegel <lsiegel@cpeo.org>]

Arsenic species in weathering mine tailings and biogenic solids at the 
Lava Cap Mine Superfund Site, CA

Andrea L Foster , Roger P Ashley  and James J Rytuba
Geochemical Transactions 2011
January 24, 2011

Abstract (provisional)

Background

A realistic estimation of the health risk of human exposure to 
solid-phase arsenic (As) derived from historic mining operations is a 
major challenge to redevelopment of California's famed "Mother Lode" 
region. Arsenic, a known carcinogen, occurs in multiple solid forms that 
vary in bioaccessibility. X-ray absorption fine-structure spectroscopy 
(XAFS) was used to identify and quantify the forms of As in mine wastes 
and biogenic solids at the Lava Cap Mine Superfund (LCMS) site, a 
historic "Mother Lode" gold mine. Principal component analysis (PCA) was 
used to assess variance within water chemistry, solids chemistry, and 
XAFS spectral datasets. Linear combination, least-squares fits 
constrained in part by PCA results were then used to quantify arsenic 
speciation in XAFS spectra of tailings and biogenic solids.

Results

The highest dissolved arsenic concentrations were found in Lost Lake 
porewater and in a groundwater-fed pond in the tailings deposition area. 
Iron, dissolved oxygen, alkalinity, specific conductivity, and As were 
the major variables in the water chemistry PCA. Arsenic was, on average, 
14 times more concentrated in biologically-produced iron (hydr)oxide 
than in mine tailings....


For the entire abstract and a link to the full article, see
http://www.geochemicaltransactions.com/content/12/1/1/abstract

--


Lenny Siegel
Executive Director, Center for Public Environmental Oversight
a project of the Pacific Studies Center
278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org



_______________________________________________
Brownfields mailing list
Brownfields@lists.cpeo.org
http://lists.cpeo.org/listinfo.cgi/brownfields-cpeo.org