Fixation, transformation, and mobilization of arsenic in sediments

Brannon, James M.; Patrick, W. H.

doi:10.1021/es00159a005

Cited by 184 publications

(98 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Concentrations of As in sediment porewaters have been found to exceed those in overlying lake waters at other mineimpacted sites by a factor of up to 60 (Crecelius, 1975;Chapman et al, 1983). In anoxic waters, these concentration gradients drive upward diusion of As (both As(III) and As(V)) into the lake water column, a process that is accelerated by sediment compaction (Aggett and O'Brien, 1985;Brannon and Patrick, 1987;Azcue et al, 1994). Hence As attenuated in sediments is remobilized and may be dispersed in the lake during the next winter mixis.…”

Section: Predictions For Arsenic Mobility At Don Pedro Reservoirmentioning

confidence: 99%

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Savage

Tingle

O’Day

et al. 2000

Applied Geochemistry

381

126

View full text Add to dashboard Cite

Arsenian pyrite, formed during Cretaceous gold mineralization, is the primary source of As along the Melones fault zone in the southern Mother Lode Gold District of California. Mine tailings and associated weathering products from partially submerged inactive gold mines at Don Pedro Reservoir, on the Tuolumne River, contain H20±1300 ppm As. The highest concentrations are in weathering crusts from the Clio mine and nearby outcrops which contain goethite or jarosite. As is concentrated up to 2150 ppm in the ®ne-grained (<63 mm) fraction of these Fe-rich weathering products.Individual pyrite grains in albite-chlorite schists of the Clio mine tailings contain an average of 1.2 wt.% As. Pyrite grains are coarsely zoned, with local As concentrations ranging from H0 to 5 wt.%. Electron microprobe, transmission electron microscope, and extended X-ray absorption ®ne-structure spectroscopy (EXAFS) analyses indicate that As substitutes for S in pyrite and is not present as inclusions of arsenopyrite or other As-bearing phases. Comparison with simulated EXAFS spectra demonstrates that As atoms are locally clustered in the pyrite lattice and that the unit cell of arsenian pyrite is expanded by H2.6% relative to pure pyrite. During weathering, clustered substitution of As into pyrite may be responsible for accelerating oxidation, hydrolysis, and dissolution of arsenian pyrite relative to pure pyrite in weathered tailings. Arsenic K-edge EXAFS analysis of the ®ne-grained Ferich weathering products are consistent with corner-sharing between As(V) tetrahedra and Fe(III)-octahedra. Determinations of nearest-neighbor distances and atomic identities, generated from least-squares ®tting algorithms to spectral data, indicate that arsenate tetrahedra are sorbed on goethite mineral surfaces but substitute for SO 4 in jarosite. Erosional transport of As-bearing goethite and jarosite to Don Pedro Reservoir increases the potential for As mobility and bioavailability by desorption or dissolution. Both the substrate minerals and dissolved As species are expected to respond to seasonal changes in lake chemistry caused by thermal strati®cation and turnover within the monomictic Don Pedro Reservoir. Arsenic is predicted to be most bioavailable and toxic in the reservoir's summer hypolimnion. 7

show abstract

Section: Predictions For Arsenic Mobility At Don Pedro Reservoirmentioning

confidence: 99%

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Savage

Tingle

O’Day

et al. 2000

Applied Geochemistry

381

126

View full text Add to dashboard Cite

show abstract

“…Both of these elements are toxic when ingested, inhaled or absorbed through the skin. Orpiment (As 2 S 3 ), realgar (AsS) and arsenopyrite (FeAsS) are the most commonly encountered solid phases of As in the subsurface environment, and these As-bearing minerals are also concentrated in hydrothermal veins or rocks affected by hydrothermal solutions [1,2]. Hydrothermally altered rock occurs when hydrothermal solution, which is defined as the hot, watery solution that escapes from magma during the later stages of crystallization [3], invades the surrounding rock.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of arsenic and lead release from hydrothermally altered rock

Tabelin

Igarashi

2009

Journal of Hazardous Materials

120

View full text Add to dashboard Cite

This paper describes the effects of pH, dissolved oxygen (DO), redox conditions, and mixing ratio of different rocks on the leaching behaviors of As and Pb from hydrothermally altered rock as well as the functional groups incorporating As and Pb in the rock. Most of As and Pb were incorporated in the residual or crystalline phase although significant amounts were also determined to be exchangeable, with carbonates and with FeMn oxides. Under oxic conditions, As and Pb showed similar leaching behaviors at similar pH values, a higher mobilization in the acidic and alkaline regions and a minimum at circumneutral pH. The absence of DO restricted the oxidation of sulfide minerals that also contained significant quantities of As resulting in a lower As release under these conditions. Strongly reducing conditions favored the release of As by the reductive dissolution of FeMn oxides and prevention of carbonate precipitation while the same conditions immobilized Pb because of its re-precipitation under reducing conditions. In general, depending on the pH, DO, and redox conditions, the major modes of As and Pb release from these sources could be either one or more of the following mechanisms: acid dissolution, reductive dissolution, ion exchange, desorption and sulfide oxidation processes.

show abstract

“…À disponibilité géologique égale, des différences de Eh et de pH peuvent influencer de façon appréciable les quantités d'arsenic observées en solution. En effet, les variations redox dans une colonne de sédiment peuvent être à l'origine d'une remobilisation significative d'As, comme l'ont constaté plusieurs auteurs (AGGET et O'BRIEN, 1985;BRANNON et PATRICK, 1987;AZCUE et al, 1994;ELBAZ-POULICHET et al, 1997;SAVAGE et al, 2000). D'autre part, il est bien connu que les pH neutres ou basiques favorisent la désorption des oxyanions d'arsenic et leur passage en solution (EARY, 1999;SMEDLEY et KINNIBURGH, 2002).…”

Section: Distribution De Pb Et As Et Transport Des Contaminantsunclassified

Pb et As dans des eaux alcalines minières : contamination, comportement et risques (mine abandonnée de Zeïda, Maroc)

Hachimi

Founti

Bouabdli

et al. 2007

rseau

View full text Add to dashboard Cite

Des échantillons d’eau et de matière en suspension ont été prélevés le long de l’oued Moulouya et dans des lacs de carrière au niveau de l’ancien centre minier de Zeïda (Haute Moulouya, Maroc) en vue d’en évaluer la salubrité. Il est en effet important d’établir le degré et les causes éventuelles de dégradation de la qualité de ces eaux, compte tenu de leur usage à des fins tant domestiques qu’agricoles. Des résidus de traitement ont également été échantillonnés dans les haldes abandonnées.L’analyse des distributions et des variations spatio-temporelles des concentrations de Pb et As a permis de mettre en évidence que le centre minier a véritablement un impact sur la qualité des eaux de surface environnantes, malgré le caractère neutre à alcalin du drainage. Aucune ne rejoint les critères de l’Organisation mondiale de la santé en matière de Pb et As dans l’eau potable (10 µg/L), mais près de la moitié souscrit aux normes marocaines (50 µg/L). L’importance de la dégradation varie selon la saison et la localité, et le contraste entre sites a priori non dégradés et sites dégradés n’est pas toujours très prononcé. On observe même des variations à l’inverse des tendances attendues. Les résultats peuvent cependant être réconciliés en tenant compte de l’importance du transport particulaire par rapport au transport dissous au moment et au lieu de l’échantillonnage.Il appert que les minéralisations et les résidus miniers restés sur place peuvent constituer la principale source de pollution des eaux de surface de la région de Zeïda.The Upper Moulouya Basin was the location of extensive lead mining between 1930 and 1985, with three major operations near Aouli, Mibladen and Zeïda. The Moulouya drains about 7.5% of the Moroccan territory and provides drinking and irrigation water to many communities over its more than 500 km path. It is thus important to determine the impact of past mining activities on its water quality, since the mining sites were abandoned with little or no rehabilitation. This paper focuses on the Zeïda area, the uppermost of these mining centres on the Moulouya.About 630,172 t of lead concentrates (40‑70% Pb) were produced between 1972 and 1985 at Zeïda. Lead was mined from carbonate and sulphide mineral deposits (cerussite, 70%; galena, 30%) mixed with barite in stratiform ore bodies hosted by Permo-Triassic arkoses. Mining left 12 Mt and 70 Mt of tailings and wastes in fully exposed piles on each side of the Moulouya, as well as a dozen water-filled open-stopes. Mine drainage is of neutral pH, thanks to the low content of residual sulphide minerals and the availability of carbonate in the tailings and host rock. The river and some quarry-lakes are tapped to fulfill domestic, agricultural and stock-breeding needs. One lake is used to directly feed Zeïda’s water network (pop. 3,000), without any water treatment.The Moulouya, upstream and downstream of Zeïda, and four lakes were sampled twice in 2002 (dry period: February; wet period: April). Temperature, electric conductivity (EC), Eh and pH were measure...

show abstract

Fixation, transformation, and mobilization of arsenic in sediments

Cited by 184 publications

References 29 publications

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Arsenic speciation in pyrite and secondary weathering phases, Mother Lode Gold District, Tuolumne County, California

Mechanisms of arsenic and lead release from hydrothermally altered rock

Pb et As dans des eaux alcalines minières : contamination, comportement et risques (mine abandonnée de Zeïda, Maroc)

Contact Info

Product

Resources

About