Assessment of Rare Earth Element Fingerprints for Distinguishing Between Site-Related Wastes and Background - 19441
- Cabrera Services, Inc. (United States)
- U.S. Army Corps of Engineers, Kansas City District (United States)
Actinides such as uranium, thorium and radium are known to be present in sites associated with various phases of the cold war weapons research, development and production. Remediation of these sites as well as others associated with chemical plants that may have generated radioactive actinide-containing wastes have been the focus of the Formerly Utilized Sites Remedial Action Program (FUSRAP) for the past 20 years. The goal is to remediate a site to established cleanup standards as efficiently and cost-effectively as possible. For radiologically-contaminated sites, one potential challenge is the presence of non-FUSRAP media such as naturally-occurring radioactive material (NORM) or technologically-enhanced naturally-occurring radioactive material (TENORM), from non-FUSRAP sources, at concentrations exceeding site cleanup standards. Such NORM and TENORM, and even byproduct radionuclides from other unrelated activities on or near the site, can be mistaken for project waste and thus incur significant additional excavation and waste transport and disposal costs. Past studies have provided examples of NORM and non-FUSRAP waste and described strategies to distinguish them from FUSRAP waste. This paper describes various sources of NORM, summarizes the types of project-related waste at some active FUSRAP sites, and identifies TENORM sites from which radionuclides could possibly migrate via various environmental pathways to nearby FUSRAP sites. The authors also examine two Case Studies that calculate distinctive elemental ratios and are examples of tools which may be used for distinguishing FUSRAP waste from other radionuclides present in natural or other man-made contributors to background. Case Study I examines two bodies of data and calculates distinctive elemental ratios between pairs of rare earth elements (REE) to see if significant differences may exist between such ratios in unregulated coal ash residue, common in fill in well-established towns and cities, and FUSRAP waste. The first group of data, consisting of eighteen sample results, was obtained from the FUSRAP Maywood Superfund Site's historical data while the second was obtained from a paper which provided extensive data (more than 100 samples) on the REE content in fly ash residues from three major coal-producing areas in the United States. This example illustrates statistically significant differences in five of six REE ratios and thus provides a potential tool for distinguishing FUSRAP waste from coal ash-based NORM. Case Study II examines differences in the mean REE:Actinide and REE:REE ratios in Welsbach-impacted sample results to distinguish project waste from background. While the purpose of this study was to distinguish project waste from background levels of the radionuclides of concern (ROC), it provides a good example of how one or more ratios could potentially be used to distinguish FUSRAP waste from NORM. Lastly, the authors recommend that future projects ensure robust characterization, that considers all potential radionuclide contributors from both FUSRAP activities as well as from other contributors to background for the region during the Planning Phase of the Data Life Cycle described within the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM). It is expected that the incremental characterization sampling and analysis costs will be dwarfed by potential savings from efforts to better delineate and limit remediation to FUSRAP wastes rather than other potentially unregulated contributors to regional background. Other agencies or commercial entities with radiological environmental liabilities similar to FUSRAP would benefit from similar considerations of REEs and other radionuclides that could contribute to regional background. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 23005337
- Report Number(s):
- INIS-US-21-WM-19441; TRN: US21V1264045671
- Resource Relation:
- Conference: WM2019: 45. Annual Waste Management Conference, Phoenix, AZ (United States), 3-7 Mar 2019; Other Information: Country of input: France; 10 refs.; available online at: https://www.xcdsystem.com/wmsym/2019/index.html
- Country of Publication:
- United States
- Language:
- English
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