Tritium migration at the Gasbuggy site: Evaluation of possible hydrologic pathways

An underground nuclear test named Gasbuggy was conducted in northwestern New Mexico in 1967. Subsequent groundwater monitoring in an overlying aquifer by the U.S. Environmental Protection Agency revealed increasing levels of tritium in monitoring well EPNG 10-36, located 132 m from the test, suggesting migration of contaminants from the nuclear cavity. There are three basic scenarios that could explain the occurrence of tritium in well 10-36: (1) introduction of tritium into the well from the land surface, (2) migration of tritium through the Ojo Alamo Formation, and (3) migration through the Pictured Cliffs Formation. The two subsurface transport scenarios were evaluated with a travel time analysis. In one, transport occurs to the Ojo Alamo sandstone either up the emplacement hole or through fractures created by the blast, and then laterally through the aquifer to the monitoring well. In the other, lateral transport occurs through fractures in the underlying Pictured Cliffs detonation horizon and then migrates up the monitoring well through plugged casing connecting the two formations. The travel time analysis indicates that the hydraulic conductivity measured in the Ojo Alamo Formation is too low for lateral transport to account for the observed arrival of tritium at the monitoring well. This suggests transport either through fractures intersecting the Ojo Alamo close to well EPNG 10-36, or through fractures in the Pictured Cliffs and up through the bottom plug in the well. The transport scenarios were investigated using hydrologic logging techniques and sampling at the monitoring well, with the fieldwork conducted after the removal of a string of 0.05-m-diameter tubing that had previously provided the only monitoring access

C9orf72-mediated ALS and FTD: multiple pathways to disease

The discovery that repeat expansions in the C9orf72 gene are a frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has revolutionized our understanding of these diseases. Substantial headway has been made in characterizing C9orf72-mediated disease and unravelling its underlying aetiopathogenesis. Three main disease mechanisms have been proposed: loss of function of the C9orf72 protein and toxic gain of function from C9orf72 repeat RNA or from dipeptide repeat proteins produced by repeat-associated non-ATG translation. Several downstream processes across a range of cellular functions have also been implicated. In this article, we review the pathological and mechanistic features of C9orf72-associated FTD and ALS (collectively termed C9FTD/ALS), the model systems used to study these conditions, and the probable initiators of downstream disease mechanisms. We suggest that a combination of upstream mechanisms involving both loss and gain of function and downstream cellular pathways involving both cell-autonomous and non-cell-autonomous effects contributes to disease progression

Groundwater flow near the Shoal Site, Sand Springs Range, Nevada: Impact of density-driven flow

The nature of flow from a highland recharge area in a mountain range in north-central Nevada to discharge areas on either side of the range is evaluated to refine a conceptual model of contaminant transport from an underground nuclear test conducted beneath the range. The test, known as the Shoal event, was conducted in 1963 in granitic rocks of the Sand Springs Range. Sparse hydraulic head measurements from the early 1960s suggest flow from the shot location to the east to Fairview Valley, while hydrochemistry supports flow to salt pans in Fourmile Flat to the west. Chemical and isotopic data collected from water samples and during well-logging arc best explained by a reflux brine system on the west side of the Sand Springs Range, rather than a typical local flow system where all flow occurs from recharge areas in the highlands to a central discharge area in a playa. Instead, dense saline water from the playa is apparently being driven toward the range by density contrasts. The data collected between the range and Fourmile Flat suggest the groundwater is a mixture of younger, fresher recharge water with older brine. Chemical contrasts between groundwater in the east and west valleys reflect the absence of re-flux water in Fairview Valley because the regional discharge area is distant and thus there is no accumulation of salts. The refluxing hydraulic system probably developed after the end of the last pluvial period and differences between the location of the groundwater divide based on hydraulic and chemical indicators could reflect movement of the divide as the groundwater system adjusts to the new reflux condition

Field investigation at the Faultless Site Central Nevada Test Area

An evaluation of groundwater monitoring at non-Nevada Test Site underground nuclear test sites raised questions about the potential for radionuclide migration from the Faultless event and how to best monitor for such migration. With its long standing interest in the Faultless area and background in Nevada hydrogeology, the Desert Research Institute conducted a field investigation in FY92 to address the following issues: The status of chimney infilling (which determines the potential for migration); the best level(s) from which to collect samples from the nearby monitoring wells, HTH-1 and HTH-2; the status of hydraulic heads in the monitoring well area following records of sustained elevated post-shot heads. The field investigation was conducted from July 27 to 31 and August 4 to 7, 1992. Temperature and electrical conductivity logging were performed in HTH-1, HTH-2, and UC-1-P-2SR. Water samples were collected from HTH-1 and HTH-2. Lawrence Livermore National Laboratory (LLNL) also collected samples during the July trip, including samples from UC-1-P-2SR. This report presents the data gathered during these field excursions and some preliminary conclusions. Full interpretation of the data in light of the issues listed above is planned for FY93

The application of borehole logging to characterize the hydrogeology of the Faultless site, Central Nevada Test Area

The Central Nevada Test Area was the site of the Faultless underground nuclear test that could be a source of radionuclide contamination to aquifers in Hot Creek Valley, Nevada. Field studies in 1992 and 1993 have used hydrologic logging and water sampling to determine the adequacy of the current groundwater monitoring network and the status of water-level recovery to pre-shot levels in the nuclear chimney. The field studies have determined that there is a possibility for contaminant migration away from the Faultless event though the pre-event water level has not been attained, while new data raise questions about the ability of the current monitoring network to detect migration. Hydrologic logs from the postshot hole (drilled into the chimney created by the nuclear detonation) reveal inflow around 485 m below land surface. The physical and chemical characteristics of the inflow water indicate that its source is much deeper in the chimney, perhaps driven upward in a convection cell generated by heat near the nuclear cavity. Logging and sampling at monitoring wells HTH-1 and HTH-2 revealed that the completion of HTH-1 may be responsible for its elevated water level (as compared to pre-nuclear test levels) and may have also created a local mound in the water table in the alluvium that accounts for higher post-test water levels at HTH-2. This mound would serve to divert flow around the monitoring wells, so that only migration of contaminants through the underlying, higher pressure, volcanic units is currently monitored. A hydraulic high found in an abandoned hole located between the nuclear chimney and the monitoring wells further reduces the likelihood of HTH-1 or HTH-2 intercepting contaminant migration

Exercise-induced effects on a gym atmosphere

We report results of analysis of a month-long measurement of indoor air and environment quality parameters in one gym during sporting activities such as football, basketball, volleyball, badminton, boxing, and fitness. We have determined an average single person's contribution to the increase of temperature, humidity, and dust concentration in the gym air volume of 12500 m3: during 90-min exercise performed at an average heart rate of 143 ± 10 bpm, a single person evaporated 0.94 kg of water into the air by sweating, contributed 0.03 K to the air temperature rise and added 1.5 μg/m3 and 5 ng/m3 to the indoor concentration of inhalable particles (PM10) and Ca concentration, respectively. As the breathing at the observed exercise intensity was about three times faster with respect to the resting condition and as the exercise-induced PM10 concentration was about two times larger than outdoors, a sportsman in the gym would receive about a sixfold higher dose of PM10 inside than he/she would have received at rest outside.Fil: Žitnik, M.. Institute Jožef Stefan; Eslovenia. University of Ljubljana. Faculty of Mathematics and Physics; EsloveniaFil: Bučar, K.. Institute Jožef Stefan; EsloveniaFil: Hiti, B.. Institute Jožef Stefan; EsloveniaFil: Barba, Ž.. Institute Jožef Stefan; EsloveniaFil: Rupnik, Z.. Institute Jožef Stefan; EsloveniaFil: Založnik, A.. Institute Jožef Stefan; EsloveniaFil: Žitnik, E.. University of Ljubljana. Faculty of Medicine; EsloveniaFil: Rodriguez, Luis Miguel. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Mihevc, I.. University of Ljubljana. Faculty of Electrical Engineering; EsloveniaFil: Žibert, J.. Univerza Na Primorskem.; Esloveni