[en] Special analyses for plutonium were performed on 1-kg soil samples from six regional stations. This is 100 times the usual mass used for analyses. These larger samples increase the sensitivity of the plutonium analyses which is necessary to evaluate background plutonium concentrations in fallout from atmospheric nuclear weapons tests. The samples at each station were collected by taking 5 plugs, 75-mm diam and 50 mm deep, at the center and corners of a square area 10 m on a side. The five plugs were combined into one sample for radiochemical analyses. (One set of samples from Santa Cruz Lake consisted of 1-kg plugs at the four corners and center and were taken to determine variability in radionuclide concentrations within a sampling grid.) The 1-kg samples were analyzed for ²³⁸Pu and /sup 239,240/Pu. Analyses for ¹³⁷Cs, ⁹⁰Sr, total uranium, and gross gamma were done on standard-size samples. The analytical results in 1983 from the six stations are compared with similar data from 1981. There is no significant difference in the concentrations of ¹³⁷Cs, ²³⁸Pu, or ⁹⁰Sr. The average /sup 239,240/Pu/²³⁸Pu ratios for both sets of samples are similar at 23 (1981) and 15 (1983). 1 figure, 1 table

[en] A study of the distribution of moisture, tritium, and plutonium in the Mortandad Canyon aquifer indicates some infiltration of water into the underlying tuff. This infiltration was accompanied by similar movement of tritium. The concentrations of plutonium on the sediments in the aquifer were low when compared with the high concentrations in solution in an ionic complex that does not readily exchange or is adsorbed by clay minerals in the alluvium. 2 references, 4 figures, 2 tables

[en] In 1956, Area G was designated for the disposal of solid radioactive waste ranging from potentially contaminated rubber gloves and glassware to parts of obsolete buildings and equipment that cannot be decontaminated. Pit 26 was constructed in Area G during 1983. Data indicate that the pit is in compliance with the guidelines issued by the US Geological Survey in 1965 and the revised guidelines reissued in 1980 by the Waste Management Group and Environmental Surveillance Group of the Los Alamos National Laboratory. 4 references, 1 figure

[en] During 1983, snowmelt runoff was monitored at Los Alamos Canyon at State Road 4 (SR-4) and at Otowi near the Rio Grande. Los Alamos Canyon and tributary Pueblo Canyon have received low-level radioactive effluents from treatment plants, so the channel sediments contain radionuclides that are subject to transport surface runoff. Snowmelt runoff was also monitored in Pajarito Canyon at SR-4, which receives no industrial effluents. Runoff was also monitored because it drained several of the Laboratory's technical areas, one of which is used for the disposal and storage area for low-level solid radioactive wastes. The concentrations of ¹³⁷Cs, ²³⁸Pu, /sup 239,240/Pu, ³H, total uranium, and gross-gamma activity in solution samples from Los Alamos Canyon at SR-4 and Otowi were indistinguishable from radioactivity concentrations in solution samples from Pajarito Canyon. There was no significant difference in concentrations of ²³⁸Pu in suspended sediment in Los Alamos Canyon at SR-4 and at Otowi when compared with those ²³⁸Pu concentrations in Pajarito Canyon. The average concentrations of /sup 239,240/Pu in suspended sediments in Los Alamos Canyon ranged from 4.7 pCi/g at SR-4 to 2.3 pCi/g at Otowi. These were about 26 and 13 times greater than the average background /sup 230,240/Pu concentrations in Pajarito Canyon. There was little, if any, transport of radionuclides in solution surface runoff in Los Alamos Canyon, which has received treated low-level radioactive effluents. There is little, if any, transport of ²³⁸Pu in suspended sediments. The major transport of radioactivity in the suspended sediments was of /sup 239,240/Pu. 1 figure, 1 table

[en] The ¹³⁷Cs concentrations in soil from five new locations (in technical areas where radioactive materials are processed or have been processed) are at or below the maximum levels (1.4 pCi/g) found in regional soils. The ²³⁸Pu and /sup 239,240/Pu soil concentrations at Station 2 were greater than were those found in regional soils (1977 and 1978-1982 Summaries). Station 2 is located south of TA-50. The total uranium soil concentrations exceed regional background concentrations at all stations. However, these levels do not indicate contamination but reflect natural uranium leached from soil derived from the tuff. These concentrations are similar to the data collected in 1977. Uranium concentrations in soils vary and depend on the rock type that has weathered to form the soil. A comparison of the averages and standard deviations of radiochemical analyses collected in 1977 and 1983 indicates only slight variations between the 2 yr. The five new stations established in 1983 will provide long-term monitoring of the possible airborne deposition of contaminants in the areas around TA-35, TA-48, TA-50, and TA-55. Comparing 1977 with 1983 data indicates no significant increase in radioactivity of the soil adjacent to these technical areas

[en] Production of potable municipal water supplies during 1996 totaled about 1,368.1 million gallons from wells in the Guaje, Pajarito, and Otowi well fields. There was no water used from either the spring gallery in Water Canyon or from Guaje Reservoir during 1996. About 2.6 million gallons of water from Los Alamos Reservoir was used for lawn irrigation. The total water usage in 1996 was about 1,370.7 million gallons, or about 131 gallons per day per person living in Los Alamos County. Groundwater pumpage was up about 12.0 million gallons in 1996 compared with the pumpage in 1995. This report fulfills requirements specified in US Department of Energy (DOE) Order 5400.1 (Groundwater Protection Management Program), which requires the Los Alamos National Laboratory (LANL) to monitor and document groundwater conditions below Pajarito Plateau and to protect the regional aquifer from contamination associated with Laboratory operations. Furthermore, this report also fulfills special conditions by providing information on hydrologic characteristics of the regional aquifer, including operating conditions of the municipal water supply system

[en] This report documents the range and the upper limit for background concentrations of radionuclides and radioactivity in soils and river sediments that occur as natural rock-forming minerals and worldwide fallout from atmospheric nuclear weapons tests. Documentation is based on the collection of soil and sediment in northern New Mexico and analyzed for ¹³⁷Cs, ²³⁸Pu, /sup 239,240/Pu, ⁹⁰Sr, total uranium, gross gamma, and tritium. The data used to establish the statistical range and upper limit of background concentration cover a 9- or 13-year period ending in 1986. The knowledge of background levels is necessary to interpret soil and sediment data collected for the annual environmental surveillance report and other reports relating to radionuclides or radioactivity in soils and sediments. 11 refs., 1 fig., 5 tabs