HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Masscheleyn, P. H. Articles by Patrick, W. H. Search for Related Content PubMed Articles by Masscheleyn, P. H. Articles by Patrick, W. H., Jr. Agricola Articles by Masscheleyn, P. H. Articles by Patrick, W. H.

Arsenic and Selenium Chemistry as Affected by Sediment Redox Potential and pH

Lab. for Wetland Soils and Sediments, Center for Wetland Resources, Louisiana State Univ., Baton Rouge, LA 70803-7511.

^* Corresponding author.

ABSTRACT

The influence of sediment redox potential and pH on As and Se speciation and solubility was studied. Hyco Reservoir (North Carolina) sediments were equilibrated under controlled redox (500, 200, 0, and –200 mV) and pH (5, natural, and 7.5) conditions. Redox potential and pH affected both speciation and solubility of As and Se. Under oxidized conditions As solubility was low and 87% of the As in solution was present as As(V). Upon reduction, As(III) became the major As species in solution, and As solubility increased. Total As in solution increased approximately 25 times upon reduction to –200 mV. No organic arsenicals were detected. In contrast to As, Se solubility reached a maximum under highly oxidized (500 mV) conditions and decreased significantly upon reduction. Selenium(VI) was the predominant dissolved Se species present at 500 mV. At 200 and 0 mV, Se(IV) became the most stable oxidation state of Se. Under strongly reduced conditions (–200 mV) oxidized Se species were no longer detectable and Se solubility was controlled by the formation of elemental Se and/or metal selenides. Biomethylation of Se was important under oxidized and moderately reduced conditions (500, 200, and 0 mV). More alkaline conditions (pH 7.5) resulted in both greater As and Se concentrations in solution. Dissolved As and Se increased up to 10 and 6 times, respectively, as compared to the more acidic equilibrations.

This article has been cited by other articles:

				P. M. Fox and H. E. Doner Accumulation, Release, and Solubility of Arsenic, Molybdenum, and Vanadium in Wetland Sediments J. Environ. Qual., November 1, 2003; 32(6): 2428 - 2435. [Abstract] [Full Text] [PDF]

				K. L. Linge and C. E. Oldham Arsenic Remobilization in a Shallow Lake: The Role of Sediment Resuspension J. Environ. Qual., May 1, 2002; 31(3): 822 - 828. [Abstract] [Full Text] [PDF]

				P. M. Fox and H. E. Doner Trace Element Retention and Release on Minerals and Soil in a Constructed Wetland J. Environ. Qual., January 1, 2002; 31(1): 331 - 338. [Abstract] [Full Text] [PDF]

				P.T. Zawislanski, H.S. Mountford, E.J. Gabet, A.E. McGrath, and H.C. Wong Selenium Distribution and Fluxes in Intertidal Wetlands, San Francisco Bay, California J. Environ. Qual., May 1, 2001; 30(3): 1080 - 1091. [Abstract] [Full Text] [PDF]

				C.A. Jones, H.W. Langner, K. Anderson, T.R. McDermott, and W.P. Inskeep Rates of Microbially Mediated Arsenate Reduction and Solubilization Soil Sci. Soc. Am. J., March 1, 2000; 64(2): 600 - 608. [Abstract] [Full Text]

				J.G. Reynolds, D.V. Naylor, and S.E. Fendorf Arsenic Sorption in Phosphate-Amended Soils during Flooding and Subsequent Aeration Soil Sci. Soc. Am. J., September 1, 1999; 63(5): 1149 - 1156. [Abstract] [Full Text]