Preliminary radiation dose assessment for the Palmerton ore storage site, Palmerton, Pennsylvania (original) (raw)

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.