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Title: Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments

Abstract

Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. Demonstrating in situ immobilization of these contaminants in vadose zones or groundwater plumes is a cost-effective remediation strategy. However, the implementation of in situ remediation requires definition of the mechanism that controls sequestration of the contaminants. One such mechanism for metals and radionuclides is co-precipitation of these elements in authigenic calcite and calcite overgrowths. Calcite, a common mineral in many aquifers and vadose zones in the arid western U.S., can incorporate divalent metals such as strontium, cadmium, lead, and cobalt into its crystal structure by the formation of solid solutions. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution, solid solution properties of the trace metal in calcite, and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning and how this may occur in aquifers and vadose environments is lacking. The focus of the research proposed here is to investigate the facilitated partitioning of metal andmore » radionuclides by their coprecipitation with calcium carbonate. Our specific research objectives include: (1) Elucidating the mechanisms and rates of microbially facilitated calcite precipitation and divalent cation adsorption/co-precipitation occurring in a natural aquifer and vadose zone perched water body as a result of the introduction of urea. (2) Assessing the effects of spatial variability in aquifer host rock and the associated hydro/biogeochemical processes on calcite precipitation rates and mineral phases within an aquifer and a vadose zone perched water body.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Idaho National Engineering and Environmental Lab., Idaho Falls, ID; University of Toronto, Toronto, Ontario; Portland State University, Portland, OR (US)
Sponsoring Org.:
USDOE Office of Environmental Management (EM) (US)
OSTI Identifier:
833667
Report Number(s):
EMSP-70206-2000
R&D Project: EMSP 70206; TRN: US200430%%1725
DOE Contract Number:  
FG07-99ER15025; FG07-99ER15020
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 19 Jul 2000
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; AQUIFERS; CADMIUM; CALCITE; CALCIUM CARBONATES; CATIONS; COBALT; COPRECIPITATION; CRYSTAL STRUCTURE; IMPLEMENTATION; KINETICS; PLUMES; PRECIPITATION; RADIOISOTOPES; SOLID SOLUTIONS; STRONTIUM; STRONTIUM 90; UREA

Citation Formats

Smith, Robert W, Colwell, F ''Rick'' S., Ingram, Jani C, Ferris, F Grant, and Reysenbach, Anna-Louise. Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments. United States: N. p., 2000. Web. doi:10.2172/833667.
Smith, Robert W, Colwell, F ''Rick'' S., Ingram, Jani C, Ferris, F Grant, & Reysenbach, Anna-Louise. Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments. United States. doi:10.2172/833667.
Smith, Robert W, Colwell, F ''Rick'' S., Ingram, Jani C, Ferris, F Grant, and Reysenbach, Anna-Louise. Wed . "Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments". United States. doi:10.2172/833667. https://www.osti.gov/servlets/purl/833667.
@article{osti_833667,
title = {Calcite Precipitation and Trace Metal Partitioning in Groundwater and the Vadose Zone: Remediation of Strontium-90 and Other Divalent Metals and Radionuclides in Arid Western Environments},
author = {Smith, Robert W and Colwell, F ''Rick'' S. and Ingram, Jani C and Ferris, F Grant and Reysenbach, Anna-Louise},
abstractNote = {Radionuclide and metal contaminants are present in the vadose zone and groundwater throughout the U.S. Department of Energy (DOE) weapons complex. Demonstrating in situ immobilization of these contaminants in vadose zones or groundwater plumes is a cost-effective remediation strategy. However, the implementation of in situ remediation requires definition of the mechanism that controls sequestration of the contaminants. One such mechanism for metals and radionuclides is co-precipitation of these elements in authigenic calcite and calcite overgrowths. Calcite, a common mineral in many aquifers and vadose zones in the arid western U.S., can incorporate divalent metals such as strontium, cadmium, lead, and cobalt into its crystal structure by the formation of solid solutions. The rate at which trace metals are incorporated into calcite is a function of calcite precipitation kinetics, adsorption interactions between the calcite surface and the trace metal in solution, solid solution properties of the trace metal in calcite, and also the surfaces upon which the calcite is precipitating. A fundamental understanding of the coupling of calcite precipitation and trace metal partitioning and how this may occur in aquifers and vadose environments is lacking. The focus of the research proposed here is to investigate the facilitated partitioning of metal and radionuclides by their coprecipitation with calcium carbonate. Our specific research objectives include: (1) Elucidating the mechanisms and rates of microbially facilitated calcite precipitation and divalent cation adsorption/co-precipitation occurring in a natural aquifer and vadose zone perched water body as a result of the introduction of urea. (2) Assessing the effects of spatial variability in aquifer host rock and the associated hydro/biogeochemical processes on calcite precipitation rates and mineral phases within an aquifer and a vadose zone perched water body.},
doi = {10.2172/833667},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jul 19 00:00:00 EDT 2000},
month = {Wed Jul 19 00:00:00 EDT 2000}
}

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