CaltechAUTHORS
  A Caltech Library Service

A Gel Probe Equilibrium Sampler for Measuring Arsenic Porewater Profiles and Sorption Gradients in Sediments: II. Field Application to Haiwee Reservoir Sediment

Campbell, Kate M. and Root, Robert and O’Day, Peggy A. and Hering, Janet G. (2008) A Gel Probe Equilibrium Sampler for Measuring Arsenic Porewater Profiles and Sorption Gradients in Sediments: II. Field Application to Haiwee Reservoir Sediment. Environmental Science and Technology, 42 (2). pp. 504-510. ISSN 0013-936X. https://resolver.caltech.edu/CaltechAUTHORS:20170320-065640338

[img] PDF - Supplemental Material
See Usage Policy.

234Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20170320-065640338

Abstract

Arsenic (As) geochemistry and sorption behavior were measured in As- and iron (Fe)-rich sediments of Haiwee Reservoir by deploying undoped (clear) polyacrylamide gels and hydrous ferric oxide (HFO)-doped gels in a gel probe equilibrium sampler, which is a novel technique for directly measuring the effects of porewater composition on As adsorption to Fe oxides phases in situ. Arsenic is deposited at the sediment surface as As(V) and is reduced to As(III) in the upper layers of the sediment (0–8 cm), but the reduction of As(V) does not cause mobilization into the porewater. Dissolved As and Fe concentrations increased at depth in the sediment column driven by the reductive dissolution of amorphous Fe(III) oxyhydroxides and conversion to a mixed Fe(II, III) green rust-type phase. Adsorption of As and phosphorous (P) onto HFO-doped gels was inhibited at intermediate depths (10–20 cm), possibly due to dissolved organic or inorganic carbon, indicating that dissolved As concentrations were at least partially controlled by porewater composition rather than surface site availability. In sediments that had been recently exposed to air, the region of sorption inhibition was not observed, suggesting that prior exposure to air affected the extent of reductive dissolution, porewater chemistry, and As adsorption behavior. Arsenic adsorption onto the HFO-doped gels increased at depths >20 cm, and the extent of adsorption was most likely controlled by the competitive effects of dissolved phosphate. Sediment As adsorption capacity appeared to be controlled by changes in porewater composition and competitive effects at shallower depths, and by reductive dissolution and availability of sorption sites at greater burial depths.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/es071120aDOIArticle
http://pubs.acs.org/doi/abs/10.1021/es071120aPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/es071120aPublisherSupporting Information
Additional Information:© 2008 American Chemical Society. Received 13 May 2007. Date accepted 5 October 2007. Published online 12 December 2007. Published in print 1 January 2008. This work was supported by funding from NSF BES-0201888, BES-0201943, and EAR-0525387. We thank the Los Angeles Department of Water and Power (LADWP), particularly Gary Stolarik, Stanley Richardson, and Fred Richardson, for access to Haiwee Reservoir. We also thank Nathan Dalleska for analytical support and Mike Vondrus for gel probe construction. Portions of this research were carried out at the Stanford Synchrotron Radiation Laboratory, a national users facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.
Funders:
Funding AgencyGrant Number
NSFBES-0201888
NSFBES-0201943
NSFEAR-0525387
Department of Energy (DOE)UNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20170320-065640338
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170320-065640338
Official Citation:A Gel Probe Equilibrium Sampler for Measuring Arsenic Porewater Profiles and Sorption Gradients in Sediments: II. Field Application to Haiwee Reservoir Sediment Kate M. Campbell, Robert Root, Peggy A. O’Day, and Janet G. Hering Environmental Science & Technology 2008 42 (2), 504-510 DOI: 10.1021/es071120a
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75222
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:20 Mar 2017 14:59
Last Modified:03 Oct 2019 16:48

Repository Staff Only: item control page