Selenium speciation, mobility, and availability from a coal-mining reclamation site: An environmental impact
Knowledge of selenium's chemical speciation is necessary for understanding the trace element's mobility and bioavailability. The mobility of many trace element chemical species is controlled by such chemical parameters as pH, soil moisture content, and redox potential. The necessity for selenium as a nutritional as a nutritional requirement adds a new dimension to the element selenium. Previously, selenium had been established as a toxic agent in food and feed crops. Selenium as the selenate species is predominant in strong oxidizing condition, becoming the most soluble and less adsorbing on soil matrices, and, thus the more bioavailable Se form. Redox potential and pH quantify the redox environment in aqueous soil systems. Selenium availability at various soil pH and redox potentials can lead to a better understanding of soil Se and contribute to management schemes needed to eliminate Se problems associated with reclamation activities with the surface mining of coal. Research investigation considered the field measurement of redox potential and pH variations which may occur in Oklahoma soils associated with mining and reclamation activities on potential Se speciation. Also, the magnitude of selenate and selenite adsorption in water-saturated soil columns was measured to determine the mobility of selenium through overburden materials used as reclamation material. In-situ field monitoring systems were used to determine subsurface soil moisture content and the oxidation-reduction potential characteristic. Soil samples were analyzed for pH using appropriate soil chemical analysis procedures. The Toxicity Characteristic Leaching Procedure data obtained indicates less than 0.1 mg Se/kg sample in composite soils collected from a reclaimed mining site in Okmulgee County, Oklahoma. Comparison of pH and Eh data measured in overburden used for reclamation fill, predicted the predominant Se species to be elemental Se, HseO[sub 3][sup [minus]], or SeO[sub 3][sup 2[minus]].
- Research Organization:
- Oklahoma Univ., Norman, OK (United States)
- OSTI ID:
- 5570759
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
01 COAL, LIGNITE, AND PEAT
COAL MINING
LAND RECLAMATION
SELENIUM COMPOUNDS
BIOLOGICAL AVAILABILITY
CHEMICAL ANALYSIS
ENVIRONMENTAL TRANSPORT
SOILS
PH VALUE
REDOX POTENTIAL
OVERBURDEN
SURFACE MINING
MASS TRANSFER
MINING
540250* - Environment
Terrestrial- Site Resource & Use Studies- (1990-)
010900 - Coal
Lignite
& Peat- Environmental Aspects