Profiles of the redox-sensitive trace elements As, Sb, V, Mo and U in the Tyro and Bannock Basins (eastern Mediterranean)

Weijden, C. H. Van der; Middelburg, Jack J.; Lange, Gert J. de; Sloot, H.A. van der; Hoede, D.; Woittiez, J. R. W.

doi:10.1016/0304-4203(90)90037-d

Cited by 53 publications

(6 citation statements)

References 36 publications

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“…The redox state of Sb in a number of anoxic marine environments reveals the following pattern ( − ): at depth, where HS - first appears, Sb III concentrations rise, but Sb V never disappears completely. This observation has intrigued previous workers.…”

Section: Discussionmentioning

confidence: 99%

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Antimony Speciation in Alkaline Sulfide Solutions: Role of Zerovalent Sulfur

Helz

Valerio

Capps

2002

Environ. Sci. Technol.

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Antimony is subject to a lower drinking water standard than arsenic, its notorious group 15 cohort in the periodic table. Both elements often co-vary in nature and are fairly soluble under reducing, alkaline conditions. Of the two, much less is known about the environmental chemistry of Sb. Measurements of Sb solubility in sulfidic solutions equilibrated with stibnite (Sb2S3) and orthorhombic sulfur reveal the existence of two new complexes that may control Sb behavior in many reducing environments. Formation reactions and stability constants (23 +/- 2 degrees C) are HS- + S(s) + Sb2S3(s) <==> HSb2S5-, log K = -1.47 +/- 0.17; and HS- + 2S(s) + Sb2S3(s) <==> Sb2S6(2-) + H+, log K = -9.55 +/- 0.07. The first complex is a mixed-valence Sb(III,V) complex; the second is an Sb(V) complex. Their stability in sulfidic solutions may explain previously puzzling evidence of Sb(V) in natural anoxic environments. Owing to these complexes, zerovalent S can enhance stibnite solubility up to 3 orders of magnitude. In neutral-to-alkaline, reducing environments, less than 7 microM HS- will transform O-coordinated, electrically neutral Sb(OH)3o to predominantly anionic S-coordinated complexes. This transformation could diminish the adsorption of Sb to negatively charged mineral surfaces, lowering retardation factors in anoxic aquifers.

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Section: Discussionmentioning

confidence: 99%

“…The implication is that sulfidic solutions, which form only in reducing environments, need not mobilize Sb only in the lowest of its two common oxidation states (III and V). Indeed, both aqueous Sb V and Sb III have been reported in sulfidic marine environments ( − ), but Sb V has not been satisfactorily explained.…”

Section: Introductionmentioning

confidence: 99%

Antimony Speciation in Alkaline Sulfide Solutions: Role of Zerovalent Sulfur

Helz

Valerio

Capps

2002

Environ. Sci. Technol.

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“…Thus, in May, the frequent appearance of arsenite in the Patuxent River may be caused by the spring bloom, brought on by increased light idized to arsenate, which will persist in the dissolved form. Arsenic enrichment has been observed in anoxic bottom waters in several basins, including Saanich Inlet, Puget Sound (Peterson and Carpenter 1983), the Baltic Sea (Andreae and Froelich 1984), and the eastern Mediterranean ( Van der Weijden et al 1990). …”

Section: Arsenatementioning

confidence: 99%

“…Two inorganic forms are commonly found in nature. Arsenate (AS0 4 3-), the oxidized form, is the most common, while arsenite (As0 2 -) is found predominantly in reducing conditions such as sediment pore waters or anoxic bottom waters (Andreae 1978(Andreae , 1979Peterson and Carpenter 1983;Andreae and Froelich 1984;Aggett and O'Brien 1985; Van der Weijden et al 1990). In oxic water or sediment, arsenite oxidizes relatively rapidly, with a half-time on the order of days, depending upon temperature, pH, biological activity, and the presence of iron and manganese hydroxides (Johnson and Pilson 1975;Scudlark andJohnson 1982;De Vitre et al 1991).…”

Section: Introductionmentioning

confidence: 99%

The Annual Cycle of Arsenic in a Temperate Estuary

Riedel

1993

Estuaries

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Dissolved concentrations of four forms of arsenic: arsenite, arsenate, monomethylarsenic, and dimethylarsenic, were measured in the Patuxent River Estuary near Benedict, Maryland, over two annual cycles. In each year, total arsenic concentrations peaked in the summer, in lateJuly and August, while minimum concentrations occurred in winter. Except in late winter, arsenate was a predominant form of arsenic present. In late winter and spring, dimethylarsenic was also a predominant form. A period of monomethylarsenic abundance occurred in summer, following the predominance of dimethylarsenic. Arsenite occurred irregularly in spring. Concurrent temperature and salinity measurements indicate that total arsenic concentrations rose before the summer increase in salinity, suggesting an arsenic source other than the end members, the Patuxent River or Chesapeake Bay.

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“…Sb(III) has been detected in surface waters where its presence seems to be mainly due to phytoplanktonic activity ( − ). Sb(III) is the main Sb species in anoxic waters ( − ) and porewaters (). Except for highly contaminated areas, Sb concentrations in sediments are in the order of a few μg/g or less.…”

Section: Introductionmentioning

confidence: 99%

Distribution and Early Diagenesis of Antimony Species in Sediments and Porewaters of Freshwater Lakes

Chen

Deng

Filella

et al. 2003

Environ. Sci. Technol.

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The study identifies the role played by different components of natural aquatic systems on the poorly known geochemistry of antimony. Different chemical forms of antimony were measured in porewaters and sediments of two Sudbury lakes characterized by contrasting redox conditions at the sediment-water interface. In porewaters, Sb(III) was present under reducing conditions where it could exist as SbS2- according to thermodynamic calculations. Sb(V) was detected mainly under oxic and mildly reducing environments where its presence was attributed to the oxidizing effect of iron and manganese oxyhydroxides or to the slow kinetics of reduction by dissolved sulfide or possible complexation by it. A third form of Sb identified as refractory was obtained after UV irradiation of the water samples, suggesting an association of Sb to low molecular weight natural organic matter. The distribution of Sb in sediments of the two lakes revealed (through the comparison of profiles and statistical correlations) the importance of iron and manganese oxyhydroxides in controlling the behavior of Sb, particularly in the lake where the interface was clearly oxic. Porewater profiles indicate that the dissolution of manganese and iron oxyhydroxides under anoxic conditions leads to the simultaneous release of dissolved Sb previously sorbed onto those compounds. In reducing sediments, the control of the solubility of Sb by iron sulfides is suggested.

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Profiles of the redox-sensitive trace elements As, Sb, V, Mo and U in the Tyro and Bannock Basins (eastern Mediterranean)

Cited by 53 publications

References 36 publications

Antimony Speciation in Alkaline Sulfide Solutions: Role of Zerovalent Sulfur

Antimony Speciation in Alkaline Sulfide Solutions: Role of Zerovalent Sulfur

The Annual Cycle of Arsenic in a Temperate Estuary

Distribution and Early Diagenesis of Antimony Species in Sediments and Porewaters of Freshwater Lakes

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