000158274 001__ 158274
000158274 005__ 20181203022133.0
000158274 0247_ $$2doi$$a10.1021/es071120a
000158274 022__ $$a0013936X
000158274 02470 $$2Scopus$$a2-s2.0-40949138511
000158274 037__ $$aARTICLE
000158274 245__ $$aA gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: II. Field application to Haiwee reservoir sediment
000158274 260__ $$c2008
000158274 269__ $$a2008
000158274 336__ $$aJournal Articles
000158274 520__ $$aArsenic (As) geochemistry and sorption behavior were measured in As- and iron (Fe)-rich sediments of Haiwee Reservoir by deploying undoped (clear) polyacrylamide gels and hydrous ferric oxide (HFO)-doped gels in a gel probe equilibrium sampler, which is a novel technique for directly measuring the effects of porewater composition on As adsorption to Fe oxides phases in situ. Arsenic is deposited at the sediment surface as As(V) and is reduced to As(III) in the upper layers of the sediment (0-8 cm), but the reduction of As(V) does not cause mobilization into the porewater. Dissolved As and Fe concentrations increased at depth in the sediment column driven by the reductive dissolution of amorphous Fe(III) oxyhydroxides and conversion to a mixed Fe(II, III) green rust-type phase. Adsorption of As and phosphorous (P) onto HFO-doped gels was inhibited at intermediate depths (10-20 cm), possibly due to dissolved organic or inorganic carbon, indicating that dissolved As concentrations were at least partially controlled by porewater composition rather than surface site availability. In sediments that had been recently exposed to air, the region of sorption inhibition was not observed, suggesting that prior exposure to air affected the extent of reductive dissolution, porewater chemistry, and As adsorption behavior. Arsenic adsorption onto the HFO-doped gels increased at depths >20 cm, and the extent of adsorption was most likely controlled by the competitive effects of dissolved phosphate. Sediment As adsorption capacity appeared to be controlled by changes in porewater composition and competitive effects at shallower depths, and by reductive dissolution and availability of sorption sites at greater burial depths. © 2008 American Chemical Society.
000158274 700__ $$aCampbell, K. M.
000158274 700__ $$aRoot, R.
000158274 700__ $$aO'Day, P. A.
000158274 700__ $$0244343$$aHering, J. G.$$g178483
000158274 773__ $$j42$$k2$$q504-510$$tEnvironmental Science and Technology
000158274 909C0 $$0252298$$pUPHCE$$xU12328
000158274 909CO $$ooai:infoscience.tind.io:158274$$particle$$pENAC
000158274 917Z8 $$x173008
000158274 937__ $$aEPFL-ARTICLE-158274
000158274 973__ $$aOTHER$$rREVIEWED$$sPUBLISHED
000158274 980__ $$aARTICLE