Title: Beryllium in Surface Soils Collected within and around Los Alamos National Laboratory: 1992–2006

A soil sampling and analysis program is the most direct means of determining the concentration, inventory, and distribution of radionuclides and radioactivity in the environment within and around nuclear facilities. This report summarizes and evaluates the concentrations of {sup 3}H, {sup 137}Cs, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, {sup 90}Sr, total uranium, and gross alpha, beta, and gamma activity in soils collected from Los Alamos National Laboratory (LANL), perimeter, and regional (background) areas over a 21-year period (1974 through 1994). Also, trends in radionuclide concentrations and radioactivity over time and the total effective dose equivalent (TEDE) were determined for eachmore » site. The upper-limit regional background concentration (95% upper-confidence level) for each radionuclide and level of radioactivity were as follows: {sup 3}H (6.34 pCi mL{sup {minus}1}), {sup 137}Cs (1.13 pCi dry g{sup {minus}1}), {sup 238}Pu (0.008 pCi dry g{sup {minus}1}), {sup 239,240}Pu (0.028 pCi dry g{sup {minus}1}), {sup 241}Am (0.208 pCi dry g{sup {minus}1}), {sup 90}Sr (0.82 pCi dry g{sup {minus}1}), total uranium (4.05 {micro}g dry g{sup {minus}1}); and gross alpha (35.24 pCi dry g{sup {minus}1}), beta (13.62 pCi dry g{sup {minus}1}), and gamma (7.33 pCi dry g{sup {minus}1}) activity. Based on the average over the years, most LANL and perimeter soils contained three or more radionuclides and/or gross radioactive that were significantly higher in concentration (p < 0.05) than regional background. The net dose (TEDE minus background) for residents living on-site at LANL or along its perimeter ranged from {minus}0.3 mrem y{sup {minus}1} (east of TA-54) to 3.8 mrem y{sup {minus}1} (east of Ta-53) and from {minus}0.4 mrem y{sup {minus}1} (White Rock) to 3.6 mrem yy{sup {minus}1} (west of LANL on Forest Service land across from TA-8GT site).« less

Soil surface (0- to 2-in. depth) samples were collected from areas within and around Los Alamos National Laboratory (LANL) just after the Cerro Grande fire, analyzed for radionuclides, radioactivity, and trace elements (heavy metals), and compared to soil samples collected in 1999 from the same sites. In addition, many types of organic substances (volatile and semivolatile organic compounds, organochlorine pesticides, polychlorinated biphenyls, high explosives, and dioxin and dioxin-like compounds) were assessed in soils from LANL, perimeter, and regional sites after the fire. Results show that impacts to regional, perimeter, and on-site (mesa top) areas from smoke and fallout ash asmore » a result of the Cerro Grande fire were minimal.« less

Three separate Sampling and Analysis Plans (SAPs) were prepared for tracts C-2, C-3, and C-4. The objective of sampling was to confirm, within the stated statistical confidence limits, that the mean levels of potential radioactive residual contamination in soils in the C Tracts are documented, in appropriate units, and are below the 15 mrem/y (150 μSv/y) Screening Action Levels (SALs). Results show that radionuclide concentration upper-bound 95% confidence levels were close to background levels, with the exception of Pu-239 and Cs-137 being slightly elevated above background, and all measurements were below the ALs and meet the real property release criteriamore » for future construction or recreational use. A follow-up ALARA analysis showed that the costs of cleanup of the soil in areas of elevated concentration and confirmatory sampling would far exceed any benefit from dose reduction.« less

In 2017, soil sampling for radiological materials was conducted within Tract A-18-2 specifically for land conveyance decisions. Measurements of radionuclides in soil samples were evaluated against a recreational use scenario, and all measurements were below screening action levels for each radionuclide. The total estimated dose was less than 1 mrem/y (< 10 μSv/y) for a hypothetical recreational user (compared to a dose limit of 25 mrem/y (250 μSv/y)). Dose estimates were based on the 95% upper confidence limits for radionuclide concentrations within the Tract. Additionally, dose estimates less than 3 mrem/y are considered to be As Low As Reasonably Achievable,more » so no follow-up analysis was conducted. Release of this property is consistent with the requirements of DOE Order 458.1 and Policy 412.« less

In 2017, soil sampling for radiological materials was conducted within Tract A-18-2 at Los Alamos National Laboratory (LANL) for land conveyance decisions. Measurements of radionuclides in soil samples were evaluated against a recreational use scenario, and all measurements were below screening action levels for each radionuclide. The total estimated dose was less than 1 mrem/yr (<10 μSv/yr) for a hypothetical recreational user (compared with a dose limit of 25 mrem/yr [250 μSv/yr]). Dose estimates were based on the 95% upper confidence levels for radionuclide concentrations within the Tract. Dose estimates less than 3 mrem/yr are considered to be as lowmore » as reasonably achievable (ALARA), therefore no follow-up analysis was conducted. Release of this property is consistent with the requirements of DOE Order 458.1 (DOE 2013) and Policy 412 (LANL 2014).« less