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Storm Water Quality in Los Alamos Canyon following the Cerro Grande Fire

Description: In May 2000, the Cerro Grande Fire burned about 7400 acres of forest on the Los Alamos National Laboratory (LANL) and about 10,000 acres in watersheds above LANL on Santa Fe National Forest lands. The resulting burned landscapes raised concerns of increased storm water runoff and transport of contaminants by runoff in the canyons traversing LANL. On June 2 and 3, 2000, rain fell in the Los Alamos Canyon watershed generating storm water runoff in the canyon bottom. This event was important in that it was the first significant runoff on LANL following the fire and occurred in a canyon containing known legacy waste sites. Samples from this runoff were analyzed for radionuclide, metal, inorganic, and organic constituents. Results show radionuclide concentrations at or below previous (pre-fire) maximum levels at locations on LANL and downstream. However, greater concentrations of some fallout-associated radionuclides (cesium-137 and strontium-90) were seen arriving on LANL from upstream areas compared to pre-fire conditions. Tests indicate most of the radionuclides in the samples were bound to sediments, not dissolved in water. Most radionuclide concentrations in sediments were below LANL Screening Action Levels, with cesium-137 and strontium-90 as exceptions. Most radionuclide concentrations in samples taken at LANL's downstream boundary were greater than those taken upstream, indicating the presence of contributing sources on LANL. For comparison purposes, doses were calculated on a mrem per liter of unfiltered water basis for 11 radionuclides commonly associated with atmospheric fallout and with LANL operations. The maximum dose was 0.094 mrem per liter unfiltered water and was largely associated with plutonium-239/240. In contrast, all filtered samples had total doses less than 0.001 mrem per liter. Compared to past data, potential doses were not increased by the fire during this initial runoff event. Of the 25 metals tested for, seven were above pre-fire levels, ...
Date: April 1, 2001
Creator: Johansen, M.; Enz, B.; Gallaher, B.; Mullen, K. & Kraig, D.
Partner: UNT Libraries Government Documents Department

Air Monitoring Leads to Discovery of New Contamination at Radioactive Waste Disposal Site (Area G) at LANL

Description: Air monitoring at Area G, the low-level radioactive waste disposal area at Los Alamos National Laboratory, revealed increased air concentrations of {sup 239}Pu and {sup 241}Am at one location along the north boundary. This air monitoring location is a couple of meters north of a dirt road used to access the easternmost part of Area G. Air concentrations of {sup 238}Pu were essentially unaffected, which was puzzling because the {sup 238}Pu and {sup 239}Pu are present in the local, slightly contaminated soils. Air concentrations of these radionuclides increased about a factor of ten in early 1995 and remained at those levels until the first quarter of 1996. During the spring of 1996 air concentrations again increased by a factor of about ten. No other radionuclides were elevated and no other Area G stations showed elevations of these radionuclides. After several formal meetings didn't provide an adequate cause for the elevations, a gamma survey was performed and showed a small area of significant contamination just south of the monitor location. We found in February, 1995, a trench for a water line had been dug within a meter of so of the air stations. Then, during early 1996, the dirt road was rerouted such that its new path was directly over the unknown contamination. It appears that the trenching brought contaminated material to the surface and caused the first rise in air concentrations and then the rerouting of the road over the contamination caused the second rise, during 1996. We also found that during 1976 and 1977 contaminated soils from the clean-up of an old processing facility had been spread over the filled pits in the vicinity of the air monitors. These soils were very low in 238Pu which explains why we saw very little {sup 238}Pu in the increased air concentrations. ...
Date: June 8, 1999
Creator: Kraig, D.H. & Conrad, R.C.
Partner: UNT Libraries Government Documents Department

Radionuclide and Heavy Metal Concentrations in Fish from the Confluences of Major Canyons That Cross Los Alamos National Laboratory Lands with the Rio Grande

Description: Bottom-feeding fish--catfish, suckers, and carp--that were collected from the confluences of some of the major canyons that cross LANL lands with the Rio Grande (RG) exhibited similar radionuclide (with the exception of {sup 90}Sr), and nonradionuclide concentrations to fish collected upstream of any potential LANL contamination sources. Strontium-90 concentrations in fish from LANL canyons/RG may be associated with LANL operations; however, the concentrations of {sup 90}Sr in fish decrease to background concentrations further downstream of LANL at CR. And, based on the most conservative assumptions (a 95% source term and maximum consumption rate), LANL operations do not result in significant doses to the general public from consuming fish along the length of the RG as it passes through the eastern edge of LANL lands to CR. Moreover, since over 85% of the doses were a result of {sup 90}Sr detected in the muscle plus bone portions of the fish and most of the {sup 90}Sr is associated with the bone, the doses to people that consume only the edible portions of the fish (muscle only), would be significantly lower.
Date: February 1, 1999
Creator: Kraig, D.H.; Naranjo, L. Jr.; Mullen, M.A. & Fresquez, P.R.
Partner: UNT Libraries Government Documents Department

Direct Penetrating Radiation Monitoring Systems: Technical Evaluation for Use at Area G, Los Alamos National Laboratory

Description: Recent advances and commercialization of electret-ion-chamber (EIC) technology for photon measurements prompted us to consider EKs as a replacement for our TLD system. After laboratory tests indicated that both systems gave adequate results for controlled exposures, throughout 1998 we conducted field tests with paired TLDs and EICS, in LANL technical areas and in public areas. We had approximately 30 paired sampling sites at Area G. At each sampling site, we deployed three TLDs and three EICS. The EICS were contained in air-tight jars, each of which was placed in a Tyvek envelope and hung about 1 m above the ground. The dosimeters were read (and, if necessary, replaced) every three months. At the sites outside Area G, the TLD readings for the first two quarters were statistically significantly higher than those of the EICS: group average exposures were 38 and 36, compared with 33 mR (both quarters) for the EICS; during quarter 3, the EIC average (40 mR) was higher than the TLD average (34 mR); and during quarter 4, the two systems were statistically the same: EIC = 42, TLD = 41 with a p-value of 0.61. We are still evaluating these differences and performing additional laboratory studies to determine causes. At the Area G sites,we noticed that several of the TLDs gave much higher readings than their co-located EICS; we believe that the TLDs were over-responding by {approx}50% to the low-energy (60-keV) gamma radiation associated with {sup 241}Am, whereas the EICS were responding accurately. We conclude that EICS are more accurate at a wide range of gamma energies and are preferable to TLDs in environments where a significant fraction of the photons are low energy.
Date: October 1, 1999
Creator: Kraig, D.; Treadaway, W. A. & Wechsler, R. J.
Partner: UNT Libraries Government Documents Department

Radionuclide Concentrations in Deer and Elk from Los Alamos National Laboratory: 1991-1998

Description: Mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) forage in many areas at Los Alamos National Laboratory (LANL) that may contain radioactivity above natural and/or worldwide fallout levels. This paper summarizes radionuclide concentrations 3H, 90Sr, 137Cs, 238Pu, 239,240Pu, 241Am, and total uranium in muscle and bone tissue of deer and elk collected from LANL lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer and elk collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer and elk collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDES (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (51 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.220, deer bone = 3.762, elk muscle = 0.117, and elk bone = 1.67 mrendy. AU CEDES were far below the International Commission on Radiological Protection guideline of 100 mrem/y, and the highest muscle plus bone CEDE (4.0 mrendy) corresponded to a RECF of 2E-06 which is far below the Environmental ...
Date: December 1, 1998
Creator: Kraig, D. H.; Ferenbaugh, J. K.; Biggs, J. R.; Bennett, K. D.; Mullen, M. A. & Fresquez, P. R.
Partner: UNT Libraries Government Documents Department