A COMPARISON OF ASH GEOCHEMISTRIES FROM THE CERRO GRANDE AND VIVEASH FIRES, NORTHERN NEW MEXICO

The Cerro Grande Fire burned approximately 48,000 acres, roughly 8,000 of which were located within the boundaries of Los Alamos National Laboratory (Laboratory), a nuclear weapons facility. Ash produced as a result of the fire will concentrate inorganic constituents as well as fallout radionuclides from historic above-ground nuclear tests. The sampling and analysis of trees, including douglas fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) with ages of roughly 50 years, was conducted in the Cerro Grande burn area to provide baseline data on the uptake of chemicals of concern by common vegetative species surrounding the Laboratory. Data from the wood pulp, bark and ground litter will aid in establishing "baseline" concentrations for Cerro Grande forest fire ash by assessing inorganics and radionuclides present in leaves and needles stemming from uptake in trees during the nutrient cycling process. The data may also provide insight into the observed geochemical changes in soil, sediment, surface water and ground water. In addition to the Cerro Grande samples, douglas fir, ponderosa pine and ground litter samples from the Viveash burn area were collected to provide comparable data from similar vegetation outside the direct influence of Laboratory activities. This should allow for the assessment of possible impacts to baseline ash concentrations that may be influenced by historic and current Laboratory operations. The Viveash Fire burn area is located in the Santa Fe National Forest approximately 6 miles northeast of Pecos, New Mexico (roughly 45 miles east-southeast of the Laboratory) and covers roughly 28,000 acres. All samples collected were analyzed for metals, cyanide, isotopic uranium, isotopic plutonium, isotopic thorium, americium-241, strontium-90, gamma spectroscopy and gross alpha/beta. Analytical results of the vegetation samples collected are pending but will be presented.