Selenium source identification and biogeochemical processes controlling selenium in surface water and biota, Kendrick Reclamation Project, Wyoming, U.S.A.

Naftz, David L.; See, Randolph B.; Ramirez, Pedro

doi:10.1016/0883-2927(93)90028-f

Cited by 11 publications

(6 citation statements)

References 16 publications

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“…Extensive experimental and field studies have concluded that redox potential and pH are the most important parameters determining chemical speciation and solubility of Se compounds in wetland environments (Elrashidi et al, 1987;Weres et al, 1989;Lemly & Smith, 1990;Masscheleyn et al, 1990Masscheleyn et al, , 1991Porcella et al, 1991;Velinsky & Cutter, 1991;Masscheleyn & Patrick, 1993;Naftz & See, 1993;Pardue & Patrick, 1995). The different possible species of selenium at various redox and pH conditions in natural environments is shown in the stability diagram of Fig.…”

Section: Discussionmentioning

confidence: 96%

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Garcı́a-Hernández

King

Velasco

et al. 2001

Journal of Arid Environments

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Section: Discussionmentioning

confidence: 96%

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Garcı́a-Hernández

King

Velasco

et al. 2001

Journal of Arid Environments

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“…The D1/D2 intensity ratio is thus equal to the Fe(II)/Fe(III) ratio inside the GR compound. At point (1), which corresponds to a few seconds after the addition of Na2SeO4, the GR doublets are met along with the FH component due to Fe(OH)2. It remains only 36% of this hydroxide, implying that a very rapid oxidation took place, due to SeO4 2anions, as testified by the concomitant decrease of the selenate concentration (Figure 2).…”

Section: Selenate Concentration During the Oxidation Of Iron-(ii)-con...mentioning

confidence: 99%

“…In many wetlands in Western United States, e.g. Kendrick in Wyoming (1) or San Joaquin valley in California (2,3), agricultural processes have caused an accumulation of Se, mainly under the form of selenate (4)(5)(6) and attributed to the leaching of Se rich soils by irrigating waters. Unfortunately, this is harmful since Se compounds are carcinogenic and teratogenic at high concentration (7).…”

Section: Introductionmentioning

confidence: 99%

Reduction of SeO₄²^- Anions and Anoxic Formation of Iron(II)−Iron(III) Hydroxy-Selenate Green Rust

Refait

Simon

Génin

2000

Environ. Sci. Technol.

146

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Iron(II)-iron(III) hydroxy-salts known as green rusts were recently discovered as minerals present in hydromorphic soils and sediments. Due to their high reactivity, they are envisioned as potential reducing agents of a number of pollutants such as nitrate, chromate, or selenate. The interaction of selenate ions with such iron(II)-containing hydroxy compounds was studied by monitoring the oxidation processes of the iron phases with transmission Mo ¨ssbauer spectroscopy measured at 14 K and by following the evolution of Se(VI) in solution by capillary electrophoresis. This interaction involved the hydroxy-selenate green rust, a compound isomorphous to the hydroxy-sulfate GR(SO 4 2-). Its chemical composition, Fe II y Fe III 2 (OH) 2(y+2) SeO 4 ‚ 8H 2 O, varied with time since y starts at 5.5 and ends at 4. GR(SeO 4 2-) was obtained from Fe(OH) 2 precipitates by simultaneous accumulation of SeO 4 2anions inside the solid phase and reduction of an equal amount of SeO 4 2anions to Se(IV) species. These species were found to be less mobile, partially bound to iron compounds and/or forming iron salts. Finally, the hydroxy-selenate GR2(SeO 4 2-) can form without any other oxidizing agent than selenate itself.

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“…3 In ecosystems with elevated Se concentrations in soil such as those of the agricultural areas of the San Joaquin Valley in California or the Kendrick site in Wyoming, Se bioaccumulation can reach levels that adversely affect wildlife. 4,5 Selenium occurs naturally in four oxidation states (-II; 0; IV; VI) which differ significantly in their nutritional and toxic relevance. The highly toxic oxidized forms of Se, selenate (Se [VI]) and (hydro)selenite (Se[IV]), are soluble in water but differ in mobility and bioavailability.…”

Section: ' Introductionmentioning

confidence: 99%

“…Anthropogenic emissions of Se, mainly by changes in land use that release Se from naturally Se-rich soils developed on shales and certain other organic-rich sedimentary rocks, cause an increase of Se concentrations in the environment . In ecosystems with elevated Se concentrations in soil such as those of the agricultural areas of the San Joaquin Valley in California or the Kendrick site in Wyoming, Se bioaccumulation can reach levels that adversely affect wildlife. , …”

Section: Introductionmentioning

confidence: 99%

Isotope Fractionation of Selenium During Fungal Biomethylation by Alternaria alternata

Schilling

Johnson

Wilcke

2011

Environ. Sci. Technol.

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The natural abundance of stable Se isotopes may reflect sources and formation conditions of methylated Se. We aimed at (1) quantifying the degree of methylation of selenate [Se(VI)] and (hydro)selenite [Se(IV)] by the fungus Alternaria alternata at pH 4 and 7 and (2) determining the effects of these different Se sources and pH values on 82Se/76Se ratios (δ82/76Se) in methylselenides. Alternaria alternata was incubated with Se(VI) and Se(IV) in closed microcosms for 11-15 days and additionally with Se(IV) for 3-5 days at 30 °C. We determined Se concentrations and δ82/76Se values in source Se(VI) and Se(IV), media, fungi, and trapped methylselenides. In Se(VI) incubations, methylselenide volatilization ended before the 11th day, and the amounts of trapped methylselenide were not significantly different among the 11-15 day incubations. In 11-15 days, 2.9-11% of Se(VI) and 21-29% of Se(IV) were methylated, and in 3-5 days, 3-5% of Se(IV) was methylated. The initial δ82/76Se values of Se(VI) and Se(IV) were -0.69±SD 0.07‰, and -0.20±0.05‰, respectively. The δ82/76Se values of methylselenides differed significantly between Se(VI) (-3.97‰ to -3.25‰) and Se(IV) (-1.44‰ to -0.16‰) as sources after 11-15 days of incubation; pH had little influence on δ82/76Se values. Thus, the δ82/76Se values of methylselenide indicate the source species of methylselenides used in this study. The strong isotope fractionation of Se(VI) is probably attributable to the different reduction steps of Se(VI) to Se(-II) which were rate-limiting explaining the low methylation yields, but not to the methylation itself. The shorter incubation of Se(IV) for 3-5 days showed a large Se isotope fractionation of at least -6‰ before the biomethylation reaction reached its end. This initial Se isotope fractionation during methylation of Se(IV) is much larger than previously published.

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Selenium source identification and biogeochemical processes controlling selenium in surface water and biota, Kendrick Reclamation Project, Wyoming, U.S.A.

Cited by 11 publications

References 16 publications

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Reduction of SeO₄²^- Anions and Anoxic Formation of Iron(II)−Iron(III) Hydroxy-Selenate Green Rust

Isotope Fractionation of Selenium During Fungal Biomethylation by Alternaria alternata

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Selenium source identification and biogeochemical processes controlling selenium in surface water and biota, Kendrick Reclamation Project, Wyoming, U.S.A.

Cited by 11 publications

References 16 publications

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Selenium, selected inorganic elements, and organochlorine pesticides in bottom material and biota from the Colorado River delta

Reduction of SeO42- Anions and Anoxic Formation of Iron(II)−Iron(III) Hydroxy-Selenate Green Rust

Isotope Fractionation of Selenium During Fungal Biomethylation by Alternaria alternata

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Reduction of SeO₄²^- Anions and Anoxic Formation of Iron(II)−Iron(III) Hydroxy-Selenate Green Rust