HR: 17:45h
AN: H32H-08    [PDF]
TI: Evaluating Ecological Effects in a Semi-arid Aquatic System Using Three Lines of Evidence
AU: * Tardiff, M F
EM: mtardiff@neptuneinc.org
AF: Neptune and Company, 1505 15th Street, Suite B, Los Alamoa, NM 87544 United States
AU: Ford-Schmid, R
AF: New Mexico Environment Department, 2905 Rodeo Park Drive East Building 1, Santa Fe, NM 87505-6303 United States
AU: Hickmott, D D
AF: Los Alamos National Laboratory, Post Office Box 1663, Los Alamos, NM 87545 United States
AB: One mission of Los Alamos National Laboratory has been to develop explosives, machine explosive charges, and test explosive components for the United States nuclear weapons program. Effluents containing high explosives and metals from machining and photographic facilities were discharged to Canon de Valle for forty years at rates up to ten million gallons per year, making up as much as half of the canyon's flow. Discharges to the canyon were discontinued in 1996. Canon de Valle has an interrupted stream that supports an herbaceous ground cover and a multi-layer canopy of conifers, oak and aspen. An ecological screening assessment and problem formulation identified barium, cadmium, copper, manganese and silver as metals of potential ecological concern for the aquatic system in the canyon. Additionally, potential impacts associated with high explosives in the aquatic system are unknown because aquatic community screening values are not available. Two field studies were designed and implemented to assess the adverse effects in the canyon's aquatic system. The first field study consisted of benthic macro-invertebrate surveys that were conducted in Canon de Valle and three reference streams. The survey was then repeated in Canon de Valle four years later to assess trends in the benthic macro-invertebrate community. The second field study consisted of toxicity testing with {it Chironomus tentans} using three locations in the Canon de Valle and one location in a reference canyon. Two rounds of toxicity testing were conducted. Each round was supported with sediment and water sampling at each location for contaminant analysis. The data from the contaminant analysis of water and sediments will be presented along with the results of the benthic macro-invertebrate surveys and the toxicity tests. An example of identifying the contaminants associated with reduced survival in a toxicity test will presented, the utility of benthic macro-invertebrate community metrics as indicators of adverse ecological effects will be discussed, and the relative importance of these three lines of evidence for assessing adverse effects in the canyon's aquatic system will be discussed.
DE: 1045 Low-temperature geochemistry
DE: 1615 Biogeochemical processes (4805)
DE: 1803 Anthropogenic effects
DE: 1851 Plant ecology
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2003 Fall Meeting