Nature and Rates of Selenium Transformations: A Laboratory Study of Kesterson Reservoir Soils

Zawislanski, P.T.; Zavarin, Mavrik

doi:10.2136/sssaj1996.03615995006000030016x

Cited by 87 publications

(71 citation statements)

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“…This rate is much higher than long-term rates measured under field conditions (Benson et al 1996). However, oxidation rates decrease as readily oxidizable Se is depleted (Zawislanski and Zavarin 1996). This has already been noted in the percent-soluble-Se present in sediments applied in the embankment plot, as shown in Figures 7c, 9c, and 10c.…”

Section: Resultsmentioning

confidence: 55%

“…Soluble Se at depth fluctuates between 5 and 15%, without any consistent long-term trends. Although future increases in soluble Se concentrations near the soil surface can be anticipated, they will likely be small (Zawislanski and Zavarin 1996). Under present conditions, downward displacement of Se is not expected to be significant due to the flat concentration gradient and low permeability of underlying sediments.…”

Section: Embankment Plot 1 (Ep-1)mentioning

confidence: 94%

“…All supernatant solutions were passed through a 0.45-micrometer (-µm) nitrocellulose filter immediately after extraction. Discussions of the limitations of this and other sequential extraction procedures may be found in Tokunaga et al (1994) and Zawislanski and Zavarin (1996). The 0.02M NaOH extraction is intended to quantify Se associated with the more readily available organic soil fractions, though not specifically organo-Se compounds.…”

Section: Lab Methodsmentioning

confidence: 99%

“…A strong acid digest procedure (Zawislanski and Zavarin 1996) is the final step of the sequential procedure and extracts total Se from post-NaOCl extraction residue. The sample is oven dried (105°Celsius) and powdered (425-µm mesh) in an agate ball-mill, then digested using hot, concentrated HNO 3 and 30% H 2 O 2 for 24 h. The residue is then refluxed using 6 M HCl, and washed several times with HCl.…”

Section: Lab Methodsmentioning

confidence: 99%

“…Current and future solubility, mobility, and bioavailability of sediment-bound Se are determined largely by Se speciation. Selenium speciation in most soils and sediments is generally dominated by chemically reduced and adsorbed forms (Tokunaga et al 1994;Zawislanski and Zavarin 1996). Periodic measurements of Se speciation give estimates of Se oxidation rates, which in turn can help predict future concentrations and distribution of soluble Se.…”

Section: Selenium Fractionation and Speciationmentioning

confidence: 99%

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Land disposal of San Luis drain sediments, Panoche Water District, South Dos Palos, California

Zawislanski¹,

Benson²,

TerBerg³

et al. 2002

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Section: Resultsmentioning

confidence: 55%

Section: Embankment Plot 1 (Ep-1)mentioning

confidence: 94%

Section: Lab Methodsmentioning

confidence: 99%

Section: Lab Methodsmentioning

confidence: 99%

Section: Selenium Fractionation and Speciationmentioning

confidence: 99%

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Land disposal of San Luis drain sediments, Panoche Water District, South Dos Palos, California

Zawislanski¹,

Benson²,

TerBerg³

et al. 2002

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Intensifying Approaches for Removal of Selenium

Wasewar

2021

Selenium Contamination in Water

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Bioremediation of selenium‐contaminated sediments and water

Frankenberger

Arshad

2001

BioFactors

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Selenium (Se) is a contaminant of agricultural irrigation-drainage water in the western United States, and the cause of wildlife deaths and grotesque deformities. Some approaches in reducing the toxic Se concentrations from contaminated sediments and water have been proposed, but most of these tend to be costly or ineffective. Bioremediation through microbial transformations of toxic Se species into nontoxic forms is being considered as an effective remedial alternative. The microbial reduction of toxic oxyanions of Se (SeO(4)(2-) and SeO(3)(2-)) into insoluble Se(0) or methylation of these species to dimethylselenide (DMSe) has been accepted as a potential bioremediation strategy for cleanup of Se-contaminated water and sediments. By conducting a series of laboratory, bench-scale and field studies, we have thoroughly investigated the remedial potential of these approaches. It was observed that microorganisms, particularly Enterobacter cloacea, are very active in reduction of Se oxyanions present in irrigation drainage water, into insoluble Se(0) and, by monitoring various environmental conditions and addition of organic amendments, the process could be stimulated manifold. Similarly, the process of biomethylation of Se in soil sediments and water was found active and highly dependent on specific carbon amendments (pectin and proteins), pH, temperature, moisture, aeration and activators (cofactors). Moreover, Se biomethylation was protein/peptide-limited rather than nitrogen-, amino acid- or carbon-limited. Crude casein and its components were equally stimulatory producing a >50-fold enhancement in DMSe yield. Methionine and methyl cobalamin stimulated DMSe production by Alternaria alternata, indicating that the coenzyme may mediate the transfer of a methyl group to the Se atom. An acute toxicity test involving inhalation of DMSe by rats revealed that DMSe is nontoxic. Experiments were scaled up from laboratory studies to field plots to verify the feasibility of this bioremediation approach. Based upon the promising results of these studies, a biotechnology prototype was developed which could be applicable for cleanup of polluted sediments and water throughout the western United States.

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Nature and Rates of Selenium Transformations: A Laboratory Study of Kesterson Reservoir Soils

Cited by 87 publications

References 0 publications

Land disposal of San Luis drain sediments, Panoche Water District, South Dos Palos, California

Land disposal of San Luis drain sediments, Panoche Water District, South Dos Palos, California

Intensifying Approaches for Removal of Selenium

Bioremediation of selenium‐contaminated sediments and water

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