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Characterization of deoximorphic features in mine waste-contaminated wetlands soils Item Info

Metal contamination from Northern Idaho mining operations has impacted wetlands along the Coeur d'Alene River floodplains resulting in a potentially hazardous environment for humans and animals. Contamination in these areas is often reported as total contaminant concentration per mass of soil, and assumes that the contaminants are homogenously distributed throughout the soil. However, pedogenesis causes distinct secondary mineral redistribution within soil profiles, and leads to selective partitioning of contaminants within the profile at macro (em) to sub-micron scales. This study examined the variability of redoximorphic features within a wetland, and contaminant enrichment in redoximorphic features relative to landscape position and water table height. Six distinct categories of Fe and Fe/Mn-rich cemented redoximorphic features were identified. The Fe and Fe/Mn-cemented redox features were found to have Cd and Pb concentrations up to four and six times greater in magnitude than soil averages. Iron and Fe/Mn-cemented redox features also had elevated levels of As and Zn. The Fe/Mn-cemented aggregates had the highest Mn concentrations (approximately 3.4�/o), were most common in the 1-2 mm size fraction, and contained the highest concentration of Pb (approximately 2.6�/o). Iron-cemented root channel linings and Fe-cemented aggregates had comparable concentrations of As, Cd, Mn, Pb, and S. Coarse sand aggregates and Fe/Mn-cemented aggregates had similar concentrations of Cd, Mn, P, and Zn. Iron-cemented aggregates and cemented root channel linings had physical similarities, while coarse sand aggregates and Fe/Mn-cemented aggregates also appeared similar. The Fe and Fe/Mn-cemented redox features were found primarily in the top 15 em of soil and decreased with soil depth. Results from this study show that pedogenesis in Coeur d'Alene wetland soils results in distinct redoximorphic features and non-homogeneous metal concentrations. Among these features are Fe and Mn - cemented aggregates that range in size from 1 to 2 mm in diameter. These aggregates have unique mineralogy and concentrate metals within the soils. Understanding contaminant partitioning and speciation in soils will allow for improved management and risk assessment of the contaminated soils.

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Title:
Characterization of deoximorphic features in mine waste-contaminated wetlands soils
Authors:
Hickey, P.
Date Created (ISO Standard):
2006-04
Description:
Metal contamination from Northern Idaho mining operations has impacted wetlands along the Coeur d'Alene River floodplains resulting in a potentially hazardous environment for humans and animals. Contamination in these areas is often reported as total contaminant concentration per mass of soil, and assumes that the contaminants are homogenously distributed throughout the soil. However, pedogenesis causes distinct secondary mineral redistribution within soil profiles, and leads to selective partitioning of contaminants within the profile at macro (em) to sub-micron scales. This study examined the variability of redoximorphic features within a wetland, and contaminant enrichment in redoximorphic features relative to landscape position and water table height. Six distinct categories of Fe and Fe/Mn-rich cemented redoximorphic features were identified. The Fe and Fe/Mn-cemented redox features were found to have Cd and Pb concentrations up to four and six times greater in magnitude than soil averages. Iron and Fe/Mn-cemented redox features also had elevated levels of As and Zn. The Fe/Mn-cemented aggregates had the highest Mn concentrations (approximately 3.4�/o), were most common in the 1-2 mm size fraction, and contained the highest concentration of Pb (approximately 2.6�/o). Iron-cemented root channel linings and Fe-cemented aggregates had comparable concentrations of As, Cd, Mn, Pb, and S. Coarse sand aggregates and Fe/Mn-cemented aggregates had similar concentrations of Cd, Mn, P, and Zn. Iron-cemented aggregates and cemented root channel linings had physical similarities, while coarse sand aggregates and Fe/Mn-cemented aggregates also appeared similar. The Fe and Fe/Mn-cemented redox features were found primarily in the top 15 em of soil and decreased with soil depth. Results from this study show that pedogenesis in Coeur d'Alene wetland soils results in distinct redoximorphic features and non-homogeneous metal concentrations. Among these features are Fe and Mn - cemented aggregates that range in size from 1 to 2 mm in diameter. These aggregates have unique mineralogy and concentrate metals within the soils. Understanding contaminant partitioning and speciation in soils will allow for improved management and risk assessment of the contaminated soils.
Subjects:
heavy metals groundwater contamination speciation mineralogy
Location:
Coeur d'Alene River
Latitude:
47.51
Longitude:
-116.15
Collection:
Coeur d'Alene Basin
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
Publisher:
University of Idaho
Contributing Institution:
University of Idaho
Type:
Text
Format:
application/pdf
Cataloger:
wbv
Date Digitized:
2012

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Source
Preferred Citation:
"Characterization of deoximorphic features in mine waste-contaminated wetlands soils", Idaho Waters Digital Library, University of Idaho Library Digital Collections, https://www.lib.uidaho.edu/digital/iwdl/items/iwdl-cda_hickey_2006.html
Rights
Rights:
Rights to the digital resource are held by the University of Idaho. http://www.uidaho.edu/
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