Area G perimeter surface-soil and single-stage water sampling: Environmental surveillance for fiscal year 1993

Abstract

ESH-19 personnel collected soil and single-stage water samples around the perimeter of Area G at Los Alamos Nationrd Laboratory to characterize possible contaminant movement through surface-water mnoff. These samples were anal yzed for tritium, total uranium, isotopic plutonium, americium-241 (soil only), and cesium-137. The metals, mercury, lead, and barium, were analyzed using xray fluorescence. Elevated levels of tritium (as high as 117,200 pCi/L) were found in soil samples afong the eastern half of the north side of Area G. To the east and south of the transuranic waste pads, the soil samples showed slight increases (300& 5000 pCi/L) above baseline tritium levels (100-1000 pCi/L for Area G soils). Only one single-stage water sample had a tritium activity greater than 2000 pCi/L. Although we propose two subsurface-to-surface tritium migration mechanisms, we do not know how well our sample results reflect possible fluctuations in the Area G near-surface tritium distribution. The uranium soil concentrations had an average vahse of 2.59 + 0.70~@g. For soil samples, the average plutonium-238 activity was 0.28 + 0.80 pCi/g and the average for total phstonium-239 and-240 was 0.21 * 0.51 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. Cesium-137 activities in soils had a wide distribution and ranged from 0.019-2.38 pCi/g. Soil mercury was detected in only 5 out of 83 samples, with the highest value at 6.1 pg/g. Other metal concentrations were found within natural background ranges. EXECUTIVE SUMMARY Area G, in Technical Area 54, has been the principaJ facility at Los Alamos Nationat Laboratory for the storage and disposal of low-level and transuranic (TRU) radioactive waste since 1957. Our investigation focused principally on the possibility of contaminated sediment movement through surface-water runoff out of the site perimeter. Soil samples were analyzed for tritium, total uranium, isotopic plutonium, americium-241, and cesium-137. The metals, mercury, lead, and barium, were analyzed using x-ray fluorescence. Filtered-water fractions from singlestage collectors were analyzed for tritium, isotopic plutonium, total uranium, and cesium-137. Filtered-sediment fractions were analyzed for isotopic plutonium only. Elevated levels of tritium (as high as 117,2W pCi/L) in soil were found for sampling locations along the eastern half of the north side of Area G, To the east and south of the TRU pads, the soil samples showed slight increases (3000-5000 pCfi) above baseline tritium levels (100-1000 pCti for soils in Area G). Six single-stage water samples had tritium activities over 1000 pCi/L, but in FY 93 only one single-stage water sample had a tritium activity greater than 2000 pCi/L. Two primary mechanisms, vapor-phase transport or capillary action, may allow tritium to move from subsurface soils to surface soils. Tritium's residence time in surface soils is unknown, however, and we d...

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

“…In July of 1999, the Soils, Each of the latter locations contained an aluminum stake with a brass tag that was stamped with a unique site identification number identified with a "G-" prefix (Conrad et al, 1995). Table 1 Previous A411 Project studies Conrad et al, 1995Conrad et al, , 1996 and one ESH-20 study …”

“…In the late 1970s, the Atomic Energy Commission issued interim operational criteria for radioactive waste areas owned or operated by them and 4 their contractors (EG&G, 1978(EG&G, , 1981Dames and Moore, 1976 Group, 1981Group, , 1983, and additional program results have been reported in the 1990s (Conrad et al, 1995. …”

“…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…”

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

“…The first soil sampling strategy (1980 to present) involves collecting grab samples along the perimeter fence line and is focused on the possibility of contaminated sediment movement through surface-water runoff out of Area G (Conrad et al, 1995). The locations chosen represent the most sensitive to possible contaminant migration.…”

Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season

“…Tritium, uranium, plutonium, and ' a variety of fission and activation products are the main isotopes in waste materials deposited at Area G (US. @SP 1997), water (Mullen et al 1996), soils/sediment (Conrad et al 1995(Conrad et al , 1996Fresquez et al 1996% 1997a, vegetation (Fresquez et al 1995(Fresquez et al , 1996b(Fresquez et al , 1997a, small mammals (l3iggs et al 1995, Bennett et al 1996, Biggs et al 1997, and bees and honey (Fresquez et al 199%) are collected fiom within and around radioactive waste disposal site Area G on an annual basis to help monitor and assess the site's impact on the surrounding environment. Two important components of this program are the assessments of soil and vegetation within and around Area G for radiological contamination.…”