Use of and Lessons Learned in Using a Surrogate Radionuclide Approach in the Remediation of Radiologically Impacted Soils and Sediments at the Middlesex Sampling Plant Site -9286 (original) (raw)
Related papers
1996
ABSTRACT Guidelines for uranium residual radioactive material in soil were derived for the B&T Metals Company site in Columbus, Ohio. This site has been identified for remedial action under the US Department of Energy`s (DOE`s) Formerly Utilized Sites Remedial Action Program (FUSRAP). Single-nuclide and total-uranium guidelines were derived on the basis of the requirement that following remedial action, the 50-year committed effective dose equivalent to a hypothetical individual living or working in the immediate vicinity of the site should not exceed a dose constraint of 30 mrem/yr for the current use and likely future use scenarios or a dose limit of 100 n-mrem/yr for less likely future use scenarios. The DOE residual radioactive material guideline computer code, RESRAD, was used in this evaluation. RESRAD implements the methodology described in the DOE manual for establishing residual radioactive material guidelines. Three scenarios were considered; each assumed that for a period of 1,000 years following remedial action, the site would be used without radiological restrictions. The three scenarios varied with regard to the type of site use, time spent at the site by the exposed individual, and sources of food and water consumed. The evaluations indicate that the dose constraint of 30 mrem/yr would not be exceeded for uranium (including uranium-234, uranium-235, and uranium-238) within 1,000 years, provided that the soil concentration of total uranium (uranium-234, uranium-235, and uranium-238) at the B&T Metals site did not exceed 1, I 00 pCi/g for Scenario A (industrial worker, current use) or 300 pCi/g for Scenario B (resident with municipal water supply, a likely future use). The dose limit of 100 mrem/yr would not be exceeded at the site if the total uranium concentration of the soil did not exceed 880 pCi/g for Scenario C (resident with an on-site water well, a plausible but unlikely future use).
Journal of Environmental Radioactivity, 2004
The Rocky Flats Nuclear Weapons Plant near Golden, CO released plutonium into the environment during almost 40 years of operation. Continuing concern over possible health impacts of these releases has been heightened by lack of public disclosure of the US Department of Energy (DOE) activities. A dose reconstruction study for the Rocky Flats facilities, begun in 1990, provided a unique opportunity for concerned citizens to design and implement field studies without participation of the DOE, its contractors, or other government agencies. The Citizens Environmental Sampling Committee was formed in late 1992 and conducted a field sampling program in 1994. Over 60 soil samples, including both surface and core samples, were collected from 28 locations where past human activities would have minimal influence on contaminant distributions in soil. Cesium-137 activity was used as a means to assess whether samples were collected in undisturbed locations. The distribution of plutonium (as 239,240 Pu) in soil was consistent with past sampling conducted by DOE, the
Regulations on the release of a radioactively contaminated site for unrestricted use are currently being established by the Environmental Protection Agency. The effective dose equivalent rate limit for the reasonably maximally exposed individual was proposed at 0.15 mSv y-1. The purpose of this study is to investigate whether or not maximum allowable soil concentrations of common radionuclides corresponding to 0.15 mSv y-1 are readily detectable. These maximum allowable soil concentrations were estimated using RESRAD. The RESRAD estimates account for an effective dose equivalent rate from external radiation plus the committed effective dose equivalent rate from internal radiation delivering 0.15 mSv y-1 to the reasonably maximally exposed individual. For Michigan and Arizona soil, the minimum detectable activities were calculated for a few radionuclides and compared to the RESRAD estimated maximum allowable concentrations. Considering only gamma-ray spectroscopy, this study found no evidence that concentrations of gamma-ray emitting radionuclides in soil contributing to 0.15 mSv y-1 were undetectable.
The distribution of depleted uranium contamination in Colonie, NY, USA
Science of The Total Environment, 2009
Uranium oxide particulates were dispersed into the environment from a factory in Colonie (NY, USA) by prevailing winds during the 1960's and '70's. Uranium concentration and isotope ratios from bulk soil samples have been accurately measured using inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) without the need for analyte separation chemistry. The natural range of uranium concentrations in the Colonie soils has been estimated as 0.7 -2.1 µg g -1 , with a geometric mean of 1 µg g -1 ; the contaminated soil samples comprise uranium up to 500 ± 40 µg g -1 . A plot of 236 U/ 238 U against 235 U/ 238 U isotopes ratios describes a mixing line between natural uranium and depleted uranium (DU) in bulk soil samples; scatter from this line can be accounted for by heterogeneity in the DU particulate. The end-member of DU compositions aggregated in these bulk samples comprises (2.05 ± 0.06) x10 -3 235 U/ 238 U, (3.2 ± 0.1) x10 -5 236 U/ 238 U, and (7.1 ± 0.3) x10 -6 234 U/ 238 U. The analytical method is sensitive to as little as 50 ng g -1 DU mixed with the natural uranium occurring in these soils. The contamination footprint has been mapped northward from site, and at least one third of the uranium in a soil sample from the surface 5 cm, collected 5.1 km NNW of the site, is DU. The distribution of contamination within the surface soil horizon follows a trend of exponential decrease with depth, which can be approximated by a simple diffusion model. Bioturbation by earthworms can account for dispersal of contaminant from the soil surface, in the form of primary uranium oxide particulates and uranyl species that are sorbed to organic matter. Considering this distribution, the total mass of uranium contamination emitted from the factory is estimated to be c. 4.8 tonnes.
Postremediation dose assessment for the former Alba Craft Laboratory site, Oxford, Ohio
1996
Potential maximum radiation dose rates were calculated for the former Alba Craft Laboratory site in Oxford, Ohio, which was involved in machining of uranium metal in the 1950s. The site is not currently being used. The residual radioactive material guideline (RESRAD) computer code, which implements the methodology described in the U.S. Department of Energy's (DOE'S) manual for establishing residual radioactive material guidelines, was used in this evaluation. Three potential land use scenarios were considered for the former Alba Craft site; the scenarios vary with regard to the type of site use, time spent at the site by the exposed individual, and sources of food consumed. Scenario A (a possible land use scenario) assumed industrial use of the site; Scenario B (a likely future land use scenario) assumed residential use of the site; and Scenario C (a possible but unlikely land use scenario) assumed the presence of a resident farmer. For Scenario A, it was assumed that any water used for domestic or industrial activities would be from uncontaminated off-site municipal sources. The water used for drinking, household purposes, and irrigation was assumed to be from uncontaminated municipal sources in Scenario B; groundwater drawn from a well located at the downgradient edge of the contaminated zone would be the only source of water for drinking, irrigation, and raising livestock in Scenario C. The results of the evaluation indicated that the DOE dose limit of 100 mrerdyr would not be exceeded for any of the scenarios analyzed. The potential maximum dose rates for Scenarios A, B, and C are 0.64,2.0, and 11 mrerdyr, respectively.
Preliminary radiation dose assessment for the Palmerton ore storage site, Palmerton, Pennsylvania
1991
Potential maximum radiation dose rates were calculated for the Palmerton ore storage site in Palmerton, Pennsylvania. The RESRAD computer code, which implements the methodology described in the U.S. Department of Energy's manual for establishing residual radioactive material guidelines, was used in this evaluation. Four potential scenarios were considered for the Palmerton ore storage site. Two scenarios were developed on the basis of industrial use of the site, and two were developed on the basis of residential use of the site. The scenarios also vary with regard to time spent at the site, sources of food consumed, and source terms. The RESRAD code was used to analyze potential radiation doses from three exposure pathways. The results indicate that the basic dose limit of 100 mrem/yr would not be exceeded in Scenarios A (industrial use, hot spot), B (industrial use, homogenous contamination), and C (residential use, homogenous contamination), but would be exceeded in Scenario D (residential use, hot spot). The potential maximum dose rates for Scenarios A, B, C, and D are 1.0 mrem/yr, 0.23 mrem/yr, 0.66 mrem/yr, and 360 mrem/yr, respectively. 1 INTRODUCTION AND HISTORY The former uranium ore storage site is located in the Palmerton, Pennsylvania, area, on New Jersey Zinc Company property. Between 1953 and 1954, approximately 300 tons of ore (0.21% uranium oxide) from the Lehigh Coal and Navigation Company were stored to support the development of eastern uranium mines and to meet the Atomic Energy Commission's (AEC's) goals for procurement and stockpiling of uranium ore. New Jersey Zinc Company accepted, sampled, and stored the ore as an agent of the AEC. The ore remained there until 1973 when, as an indirect result of the Grand Junction mill tailings legislation, the AEC initiated a program to evaluate and clean up its ore storage and stockpile locations. The AEC cleanup plan for the Palmerton site called for the removal of the ore and the first 15 cm of soil. In June 1973, the ore and soil were transported to the AEC Feed Materials Center in Fernald, Ohio, for disposal in the plant's raffinate pits. The area at the east end of the stockpile was excavated an additional 61 to 76 cm to remove some chunks of ore that were buried. This material was disposed of in New Jersey Zinc Company's slag dump. The site met the guidelines adopted by the AEC at that time and was released to the owner. As part of the Formerly Utilized Sites Remedial Action Program (FUSRAP), the U.S. Department of Energy (DOE) is implementing a radiological survey program to determine the radiological conditions at sites that were used by agencies prior to the DOE. Although the final Palmerton site report indicated that the site met the criteria as defined at the time of cleanup, the DOE determined that supporting radiological data were not sufficient to demonstrate that contemporary standards were met throughout the site. Subsequent radiological criteria and guidelines have become more stringent for the release of such sites for unrestricted use. At the request of DOE, Oak Ridge National Laboratory (ORNL) conducted a comprehensive survey of a portion of the site in July and August of 1988. The purpose of this report is to calculate potential maximum radiation dose rates for both present and possible future use conditions. The RESRAD computer code, which implements the methodology described in DOE's manual for establishing residual radioactive material guidelines (Gilbert et al. 1989), was used to perform a dose assessment for that portion of the site surveyed by ORNL. 2 SCENARIO DEFINITION Four potential exposure scenarios are considered in the dose assessment. In all scenarios, unrestricted use, at some time within 1000 years, is assumed for the Palmerton ore storage site (POSS) areas. Potential radiation doses resulting from three exposure pathways are analyzed: (1) direct exposure to external radiation from the contaminated soil material, (2) internal radiation from inhalation of contaminated dust, and (3) internal radiation from ingestion of plant foods grown in the contaminated area and irrigated with water drawn from a well adjacent to the contaminated area. On-site well water is not used for drinking because of the poor quality of shallow well water (Cottrell 1990). For Scenario D, however, it is assumed that the shallow well water is used for irrigation of garden vegetables. Also, for all scenarios, it is assumed that the worker or resident does not ingest fish, meat, or milk, from the site area. In Scenario A (industrial use, hot spot), industrial use of the site is assumed. A hypothetical person is assumed to work in the POSS loading and unloading operations 15 minutes per week, 50 weeks per year, in the vicinity of the hot spot. Industrial use is also assumed in Scenario B (industrial use, homogeneous contamination). A hypothetical person is assumed to work in the POSS area 8 hours per day (6 hours outdoors and 2 hours indoors), 5 days per week, 50 weeks per year. It is also assumed Contaminated zone b parameter: = 10.4. Based on silty clay soil at POSS.
Journal of Environmental Radioactivity, 2013
A four year investigation of the largest uranium production legacy site in Ukraine (Pridneprovsky Chemical Plant) has been carried out, including: gamma-dose mapping; indoor and outdoor 222 Rn concentrations; evaluation of tailings sites; as well as preliminary dose calculations for personnel working at the industrial site. This paper provides basic information on remediation planning, on decontamination of the former uranium extraction facilities, and the needs for proper management of the uranium residue in compliance with the best international practice.