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Performance Evaluation of Whole Body Counting Facilities in the Marshall Islands (2002-2005)

Description: The United States Department of Energy (U.S. DOE) has recently implemented a series of strategic initiatives to address long-term radiological surveillance needs at former U.S. nuclear test sites in the Marshall Islands (https://eed.llnl.gov/mi/). Local atoll governments have been actively engaged in developing shared responsibilities for protecting the health and safety of resettled and resettling population at risk from exposure to elevated levels of residual fallout contamination in the environment. Under the program, whole body counting facilities have been established at three locations in the Marshall Islands. These facilities are operated and maintained by Marshallese technicians with scientists from the Lawrence Livermore National Laboratory (LLNL) providing technical support services including data quality assurance and performance testing. We have also established a mirror whole body counting facility at the Lawrence Livermore National Laboratory as a technician training center. The LLNL facility also allows program managers to develop quality assurance and operational procedures, and test equipment and corrective actions prior to deployment at remote stations in the Marshall Islands. This document summarizes the results of external performance evaluation exercises conducted at each of the facilities (2002-2005) under the umbrella of the Oak Ridge National Laboratory Intercomparison Studies Program (ISP). The ISP was specifically designed to meet intercomparison requirements of the United States (U.S.) Department of Energy Laboratory Accreditation Program (DOELAP). In this way, the Marshall Islands Radiological Surveillance Program has attempted to establish quality assurance measures in whole body counting that are consistent with standard requirements used to monitor DOE workers in the United States. Based on ANSI N13.30, the acceptable performance criteria for relative measurement bias and precision for radiobioassay service laboratory quality control, performance evaluation, and accreditation is -25% to +50% and less than or equal to 40%, respectively.
Date: April 3, 2007
Creator: Kehl, S R; Hamilton, T; Jue, T & Hickman, D
Partner: UNT Libraries Government Documents Department

137Cs Inter-Plant Concentration Ratios Provide a Predictive Tool for Coral Atolls with Distinct Benefits Over Transfer Factors

Description: Inter-plant concentration ratios (IPCR), [Bq g{sup -1} {sup 137}Cs in coral atoll tree food-crops/Bq g{sup -1} {sup 137}Cs in leaves of native plant species whose roots share a common soil volume], can replace transfer factors (TF) to predict {sup 137}Cs concentration in tree food-crops in a contaminated area with an aged source term. The IPCR strategy has significant benefits relative to TF strategy for such purposes in the atoll ecosystem. IPCR strategy applied to specific assessments takes advantage of the fact tree roots naturally integrate 137Cs over large volumes of soil. Root absorption of {sup 137}Cs replaces large-scale, expensive soil sampling schemes to reduce variability in {sup 137}Cs concentration due to inhomogeneous radionuclide distribution. IPCR [drinking-coconut meat (DCM)/Scaevola (SCA) and Tournefortia (TOU) leaves (native trees growing on all atoll islands)] are log normally distributed (LND) with geometric standard deviation (GSD) = 1.85. TF for DCM from Enewetak, Eneu, Rongelap and Bikini Atolls are LND with GSD's of 3.5, 3.0, 2.7, and 2.1, respectively. TF GSD for Rongelap copra coconut meat is 2.5. IPCR of Pandanus fruit to SCA and TOU leaves are LND with GSD = 1.7 while TF GSD is 2.1. Because IPCR variability is much lower than TF variability, relative sampling error of an IPCR field sample mean is up 6- to 10-fold lower than that of a TF sample mean if sample sizes are small (10 to 20). Other IPCR advantages are that plant leaf samples are collected and processed in far less time with much less effort and cost than soil samples.
Date: July 17, 2007
Creator: Robison, W L; Hamilton, T F; Bogen, K; Corado, C L & Kehl, S R
Partner: UNT Libraries Government Documents Department

The Northern Marshall Islands radiological survey: A quality control program for radiochemical and gamma spectroscopy analysis

Description: From 1979 to 1989, approximately 25,000 Post Northern Marshall Islands Radiological Survey (PNMIRS) samples were collected, and over 71,400 radiochemical and gamma spectroscopy analyses were performed to establish the concentration of {sup 90}Sr, {sup 137}Cs, {sup 241}Am, and plutonium isotopes in soil, vegetation, fish, and animals in the Northern Marshall Islands. While the Low Level Gamma Counting Facility (B379) in the Health and Ecological Assessment (HEA) division accounted for over 80% of all gamma spectroscopy analyses, approximately 4889 radiochemical and 5437 gamma spectroscopy analyses were performed on 4784 samples of soil, vegetation, terrestrial animal, and marine organisms by outside laboratories. Four laboratories were used by Lawrence Livermore National Laboratory (LLNL) to perform the radiochemical analyses: Thermo Analytical Norcal, Richmond, California (TMA); Nuclear Energy Services, North Carolina State University (NCSU); Laboratory of Radiation Ecology, University of Washington (LRE); and Health and Ecological Assessment (HEA) division, LLNL, Livermore, California. Additionally, LRE and NCSU were used to perform gamma spectroscopy analyses. The analytical precision and accuracy were monitored by including blind duplicates and natural matrix standards in each group of samples analyzed. On the basis of reported analytical values for duplicates and standards, 88% of the gamma and 87% of the radiochemical analyses in this survey were accepted. By laboratory, 93% of the radiochemical analyses by TMA; 88% of the gamma-ray spectrometry and 100% of the radiochemistry analyses by NCSU; 89% of the gamma spectroscopy and 87% of the radiochemistry analyses by LRE; and 90% of the radiochemistry analyses performed by HEA`s radiochemistry department were accepted.
Date: September 1, 1995
Creator: Kehl, S.R.; Mount, M.E. & Robison, W.L.
Partner: UNT Libraries Government Documents Department

Characterization and Source Term Assessments of Radioactive Particles from Marshall Islands Using Non-Destructive Analytical Techniques

Description: A considerable fraction of radioactivity entering the environment from different nuclear events is associated with particles. The impact of these events can only be fully assessed where there is some knowledge about the mobility of particle bound radionuclides entering the environment. The behavior of particulate radionuclides is dependent on several factors, including the physical, chemical and redox state of the environment, the characteristics of the particles (e.g., the chemical composition, crystallinity and particle size) and on the oxidative state of radionuclides contained in the particles. Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized using non-destructive analytical and microanalytical methods. By determining the activity of {sup 239,240}Pu and {sup 241}Am isotopes from their gamma peaks structural information related to Pu matrix was obtained, and the source term was revealed. Composition and elemental distribution in the particles were studied with synchrotron radiation based micro X-ray fluorescence (SR-{mu}-XRF) spectrometry. Scanning electron microscope equipped with energy dispersive X-ray detector (SEMEDX) and secondary ion mass spectrometer (SIMS) were used to examine particle surfaces. Based on the elemental composition the particles were divided into two groups; particles with plain Pu matrix, and particles where the plutonium is included in Si/O-rich matrix being more heterogeneously distributed. All of the particles were identified as fragments of initial weapons material. As containing plutonium with low {sup 240}Pu/{sup 239}Pu atomic ratio, {approx}2-6%, which corresponds to weapons grade plutonium, the source term was identified to be among the safety tests conducted in the history of Runit Island.
Date: June 11, 2005
Creator: Jernstrom, J; Eriksson, M; Simon, R; Tamborini, G; Bildstein, O; Carlos-Marquez, R et al.
Partner: UNT Libraries Government Documents Department

Technical Basis Document: A Statistical Basis for Interpreting Urinary Excretion of Plutonium Based on Accelerator Mass Spectrometry (AMS) for Selected Atoll Populations in the Marshall Islands

Description: We have developed refined statistical and modeling techniques to assess low-level uptake and urinary excretion of plutonium from different population group in the northern Marshall Islands. Urinary excretion rates of plutonium from the resident population on Enewetak Atoll and from resettlement workers living on Rongelap Atoll range from <1 to 8 {micro}Bq per day and are well below action levels established under the latest Department regulation 10 CFR 835 in the United States for in vitro bioassay monitoring of {sup 239}Pu. However, our statistical analyses show that urinary excretion of plutonium-239 ({sup 239}Pu) from both cohort groups is significantly positively associated with volunteer age, especially for the resident population living on Enewetak Atoll. Urinary excretion of {sup 239}Pu from the Enewetak cohort was also found to be positively associated with estimates of cumulative exposure to worldwide fallout. Consequently, the age-related trends in urinary excretion of plutonium from Marshallese populations can be described by either a long-term component from residual systemic burdens acquired from previous exposures to worldwide fallout or a prompt (and eventual long-term) component acquired from low-level systemic intakes of plutonium associated with resettlement of the northern Marshall Islands, or some combination of both.
Date: May 1, 2007
Creator: Bogen, K; Hamilton, T F; Brown, T A; Martinelli, R E; Marchetti, A A; Kehl, S R et al.
Partner: UNT Libraries Government Documents Department

Marshall Island radioassay quality assurance program an overview

Description: The Lawrence Livermore National Laboratory has developed an extensive quality assurance program to provide high quality data and assessments in support of the Marshall Islands Dose Assessment and Radioecology Program. Our quality assurance objectives begin with the premise of providing integrated and cost-effective program support (to meet wide-ranging programmatic needs, scientific peer review, litigation defense, and build public confidence) and continue through from design and implementation of large-scale field programs, sampling and sample preparation, radiometric and chemical analyses, documentation of quality assurance/quality control practices, exposure assessments, and dose/risk assessments until publication. The basic structure of our radioassay quality assurance/quality control program can be divided into four essential elements; (1) sample and data integrity control; (2) instrument validation and calibration; (3) method performance testing, validation, development and documentation; and (4) periodic peer review and on-site assessments. While our quality assurance objectives are tailored towards a single research program and the evaluation of major exposure pathways/critical radionuclides pertinent to the Marshall Islands, we have attempted to develop quality assurance practices that are consistent with proposed criteria designed for laboratory accre
Date: September 1, 1998
Creator: Conrado, C.L.; Hamilton, T.F.; Kehl, S.R.; Robison, W.L. & Stoker, A.C.
Partner: UNT Libraries Government Documents Department