Environmental Soil Screening Levels for Cs-137 at University of Washington Medical Center
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Current radiological surveys (exposure rate measurements and smear surveys) conducted outside the University of Washington (UW) Harborview Research and Training building found no evidence of Cs-137 contamination in public walk ways, or open areas, and preliminary soil concentrations from samples upwind and downwind of the building were within global fallout levels found in the region. Additional soil and outdoor surface sampling is being considered to more fully assess the possibility of an environmental release during the incident and the radiological impact, if any. This analysis is designed to assist in the evaluation of soil sample results and provide radiation dose-based Soil Screening Levels (SSLs) to help develop sampling and analysis plans and for evaluating these measurements in the context of radiation dose limits. Soil samples could be used to answer two general questions. The first asks if any detected Cs-137 in the soil is above global fallout levels measured in the area. Calculations based on fallout levels from Beck and Bennett (2002) and NCRP 154 suggest that current global fallout levels in Seattle area soil would range up to about 3 pCi/g in undisturbed soils, but there would be large variations based on a variety of transport factors related to the urban environment surrounding the area. Based on the sample result, any measurement significantly above background could prompt additional analysis including looking at the ratio of the Cs-137 to Pu-239/240 to help identify the source of the Cs-137, that is, from global fallout or from the incident. The second question is if there is detectable Cs-137 in the soil, what is the radiological impact of the Cs-137? For this, a dose pathway analysis using the RESRAD model was done to protectively estimate soil-based dose conversion factors and SSLs for Cs-137 in soil.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1561045
- Report Number(s):
- LA-UR-19-28234
- Country of Publication:
- United States
- Language:
- English
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