Area G perimeter surface-soil and single-stage water sampling: Environmental surveillance for fiscal year 95. Progress report

Abstract

Location of Six surface soils were also submitted for metal analyses. These data were included with similar data generated for soil samples collected during FY 94 and compared with metals in background samples collected at the Area G expansion area. I List of TablesElevated levels of tritium (as high as 105,000 pCi/L) were found in perimeter soil samples during FY 95. Five single-stage water runoff samples (out of a total of 131 collected) had a tritium activity greater than 1000 pCi/L. The tritium concentrations in soils were substantially lower than those found during corresponding sampling accomplished in FY 94, but similar to tritium levels in soils collected during FY 93. Although we propose two major subsurface-to-surface tritium migration mechanisms, we do not know how well these surface sample tritium data reflect the true Area G near-surface soil tritium distribution.For soil samples, the average plutonium-238 activity was 0.539 pCi/g, whereas for plutonium-239 the average activity was 0.343 pCi/g. The locations of elevated plutonium readings in soil samples were consistent with the history of plutonium disposal at Area G, which was also reflected in the americium-241 results. Americium-241 on soils had a mean concentration of 0.202 pCi/g. Cesium-137 activities in soils had a wide distribution and ranged from 0.02 to 1.76 pCi/g. The uranium soil concentrations had an average value of 2.67 pg/g and were uniformly distributed around Area G.Of the ten metals analyzed on six perimeter soils collected around Area G, all were within the baseline concentrations for metals established from the soil sampling done in the undisturbed Area G expansion grid.Baseline or local background concentrations for future disposal operations were established for metals and radionuclides by a sampling program conducted in the proposed Area G expansion area during FY 93 and 94.Considering the amount of low level radioactive waste that has been disposed of at Area G, there is evidence of only low concentrations of radionuclides on perimeter surface soils. Consequently, little radioactivity is leaving the confines of Area G via the surface water runoff pathway. EX:ECUTIVE SUMMARYArea G, in Technical Area 54, has been the principal facility at Los Alamos National Laboratory for the storage and disposal of low-level, solid mixed, and transuranic (TRU) radioactive waste since 1957. Our investigation during FY 95 focused on defining whether surface water has moved contaminated sediments out of the Area G site perimeter. Soil samples were analyzed for tritium, total uranium, isotopic plutonium, americiu~n-241, and cesium-137. Ten metals-silver, arsenic, barium, beryllium, cadmium, chromium, mercury, nickel, lead and antimony-were analyzed on soils using standard analytical chemistry techniques (EPA SW-846). Filtered-water fractions from single-stage collectors were analyzed for tritium. Filtered-sediment fractions of the single-stage samples were analyzed for isotopic plutonium only.Elevated levels of tritium (as high as 90,500 p ...

Radionuclide Concentration in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during 2005

“…All quality assurance/quality control requirements were met by Paragon Analytics, Inc. All methods of radiochemical analyses have been described previously (Fresquez et al, 1997;Childs and Conrad, 1997) and the methods for estimating Total Propagated Analytical Uncertainty (TPU) for all radiometric analyses were described in detail previously (Nyhan et al, 2002). Radionuclide results were reported in pCi/mL of soil moisture for 3 H and pCi/g dry soil for all the others.…”

Radionuclide Concentrations in soils an Vegetation at Low-Level Radioactive Waste Disposal Area G During 2004

“…All soil samples were submitted under full chain-of-custody to Paragon Analytics, quality assurance/quality control requirements were met by Paragon Analytics, Inc. All methods of radiochemical analyses have been described previously (Fresquez et al, 1997;Childs and Conrad, 1997) and the methods for estimating Total Propagated Analytical Uncertainty (TPU) for all radiometric analyses were described in detail previously (Nyhan et al, 2002). Radionuclide results were reported in pCi/mL of soil moisture for 3 H and pCi/g dry soil for all the other isotopes.…”

Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G During the 1999 Growing Season

“…North of western end of Pit 38 near gate (outside the Area G fence) 9 Analysis, and Display (FIMAD) system (see Conrad et al, 1995 (Fresquez et al, 1996a;Childs and Conrad, 1999). The only difference in assay techniques involved 241 Am, which was determined by alpha spectroscopy for one set of samples (Fresquez et al, 1996a) and by gamma spectroscopy for the A411…”

“…Project samples (Childs and Conrad, 1999 Overstory samples were mainly from piñon pine (Pinus edulis) because piñon pine is the prevalent tree in the area (Tierney and Foxx, 1982). to collect distillate water (Salazar, 1984 (Fresquez et al, 1996b 2 Concentration for 3 H is based on soil moisture.…”

“…to collect distillate water (Salazar, 1984 (Fresquez et al, 1996b 2 Concentration for 3 H is based on soil moisture. 3 Samples without a G prefix collected at the 0-to 2-inch depth by Ecology Group ; samples with a G prefix collected at the 0-to 6-inch depth by Hazardous and Solid Waste Group (Childs and Conrad, 1999). 4 Regional statistical reference level; this is the upper (95%) level background concentrations (mean + 2 std dev) from 1992(LANL 2000.…”