7 research outputs found
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Ecological baseline studies in Los Alamos and Guaje Canyons County of Los Alamos, New Mexico. A two-year study
During the summers of 1993 and 1994, the Biological Resource Evaluations Team (BRET) of the Environmental Protection Group (ESH-8) conducted baseline studies within two canyon systems, Los Alamos and Guaje Canyons. Biological data was collected within each canyon to provide background and baseline information for Ecological Risk models. Baseline studies included establishment of permanent vegetation plots within each canyon along the elevational gradient. Then, in association with the various vegetation types, surveys were conducted for ground dwelling insects, birds, and small mammals. The stream channels associated with the permanent vegetation plots were characterized and aquatic macroinvertebrates collected within the stream monthly throughout a six-month period. The Geographic Position System (GPS) in combination with ARC INFO was used to map the study areas. Considerable data was collected during these surveys and are summarized in individual chapters
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Floristic composition and plant succession on near-surface radioactive-waste-disposal facilities in the Los Alamos National Laboratory
Since 1946, low-level radioactive waste has been buried in shallow landfills within the confines of the Los Alamos National Laboratory. Five of these sites were studied for plant composition and successional patterns by reconnaissance and vegetation mapping. The data show a slow rate of recovery for all sites, regardless of age, in both the pinon-juniper and ponderosa pine communities. The sites are not comparable in succession or composition because of location and previous land use. The two oldest sites have the highest species diversity and the only mature trees. All sites allowed to revegetate naturally tend to be colonized by the same species that originally surrounded the sites. Sites on historic fields are colonized by the old field flora, whereas those in areas disturbed only by grazing are revegetated by the local native flora
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Second annual review update preliminary risk assessment of federally protected species at the Los Alamos National Laboratory
In FY96 and FY97, preliminary assessments were conducted of the potential risk from legacy waste to the American peregrine falcon (Falco peregrimus), the bald eagle (Haliaeetus leucocephalus), and the Mexican spotted owl (Strix occidentalis lucida). Estimated doses were compared against toxicity reference values (TRVs) to generate hazard indices that included a measure of cumulative effects from multiple contaminants (radionuclides, metals, and organic chemicals). The tools used included a custom FORTRAN code ECORSK, and a geographic information system. The assessments originally included only the soil ingestion contaminant pathway. Since the initial assessments, a food consumption contaminant pathway has been added, bioaccumulation and biomagnification of some contaminants have been factored into the food consumption pathway, and some of the TRVs against which estimated doses are compared have been changed to values which relate more closely to the Aves taxonomical class. With these and other more subtle improvements in model input parameters, ECORSK has been revised and the model has been re-executed for the owl and peregrine exposure units that originally generated the highest risk indices. This report contains the updated results. On average, results indicate a small potential for impact to the peregrine falcon, but no appreciable impact to the spotted owl nor the bald eagle. The original reports cited in this document should be consulted for details on methods
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Strontium concentrations in chamisa (Chrysothamnus nauseosus) shrub plants growing in a former liquid waste disposal area in Bayo Canyon
Chamisa (Chrysothamnus nauseosus) shrub plants growing in a former liquid waste disposal site Solid Waste Management Unit [SWMU] 10-003(c) in Bayo Canyon at Los Alamos National Laboratory (LANL) were collected and analyzed for strontium ({sup 90}Sr) and total uranium. Surface soil samples were also collected from below (understory) and between (interspace) shrub canopies. Both chamisa plants growing over SWMU 10-003(c) contained significantly higher concentrations of {sup 90}Sr than a control plant -- one plant, in particular, contained 90, 500 pCi {sup 90}Sr g{sup {minus}1} ash in top-growth material. Similarly, soil surface samples collected underneath and between plants contained {sup 90}Sr concentrations above background and LANL screening action levels; this probably occurred as a result of chamisa plant leaf fall contaminating the soil understory area followed by water and/or winds moving {sup 90}Sr to the soil interspace area. Although some soil surface migration of {sup 90}Sr from SWMU 10-003(c) has occurred, the level of {sup 90}Sr in sediments collected downstream of SWMU 10-003(c) at the Bayo Canyon/State Road 5 intersection was still within regional (background) concentrations
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Uptake of strontium by chamisa (Chrysothamnus nauseosus) shrub plants growing over a former liquid waste disposal site at Los Alamos National Laboratory
A major concern of managers at low-level waste burial site facilities is that plant roots may translocate contaminants up to the soil surface. This study investigates the uptake of strontium ({sup 90}Sr), a biologically mobile element, by chamisa (Chrysothamnus nauseosus), a deep-rooted shrub plant, growing in a former liquid waste disposal site (Solid Waste Management Unit [SWMU] 10-003[c]) at Los Alamos National Laboratory (LANL), Los Alamos, New Mexico. Surface soil samples were also collected from below (understory) and between (interspace) shrub canopies. Both chamisa plants growing over SWMU 10-003(c) contained significantly higher concentrations of {sup 90}Sr than a control plant--one plant, in particular, contained 3.35 x 10{sup 6} Bq kg{sup {minus}1} ash (9.05 x 10{sup 4} pCi g{sup {minus}1} ash) in top-growth material. Similarly, soil surface samples collected underneath and between plants contained {sup 90}Sr concentrations above background and LANL screening action levels (> 218 Bq kg{sup {minus}1} dry [5.90 pCi g{sup {minus}1} dry]); this probably occurred as a result of chamisa plant leaf fall contaminating the soil understory area followed by water and/or winds moving {sup 90}Sr to the soil interspace areas. Although some soil surface migration of {sup 90}Sr from SWMU 10-003(c) has occurred, the level of {sup 90}Sr in sediments collected downstream of SWMU 10-003(c) at the LANL boundary was still within regional (background) concentrations