SciCombinator

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Concept: Proving ground

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Yuma Proving Grounds (YPG) in western Arizona is a testing range where Depleted uranium (DU) penetrators have been historically fired. A portion of the fired DU penetrators are being managed under controlled conditions by leaving them in place. The widespread use of DU in armor-penetrating weapons has raised environmental and human health concerns. The present study is focused on the onsite management approach and on the potential interactions with plants local to YPG. A 30 day study was conducted to assess the toxicity of DU corrosion products (e.g., schoepite and meta-schoepite) in two grass species that are native to YPG, Bermuda (Cynodon dactylon) and Purple Threeawn (Aristida purpurea). In addition, the ability for plants to uptake DU was studied. The results of this study show a much lower threshold for biomass toxicity and higher plant concentrations, particularly in the roots than shoots, compared to previous studies.

Concepts: Plant, Poaceae, Root, Cultural studies, Grass, Depleted uranium, Cynodon dactylon, Proving ground

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Depleted uranium (DU) from the military testing and use of armor-piercing kinetic energy penetrators has been shown to accumulate in soils; however, little is known about the toxicity of DU geochemical species created through corrosion/weathering. The purpose of the current study was to assess the toxic effects and bioaccumulation potential of field-collected DU oxides to the model terrestrial invertebrates, Eisenia fetida (earthworm) and Porcellio scaber (isopod). Earthworm studies were acute (72 h) dermal exposures or 28-d spiked soil exposures that utilized non-contaminated field-collected soils from the US Army’s Yuma and Aberdeen Proving Grounds (YPG and APG). Endpoints assessed in earthworm testing included bioaccumulation, growth, reproduction, behavior (soil avoidance), and cellular stress (neutral red uptake in coelomocytes). Isopod testing utilized spiked food and endpoints assessed included bioaccumulation, survival, and feeding behavior. Concentration-dependent bioaccumulation of DU in earthworms was observed with a maximum bioaccumulation factor (BAF) of 0.35; however, no significant reductions in survival or impacts to cellular stress were observed. Reproduction lowest observed effect concentrations of 158 and 96 mg/kg were observed in YPG and a Mississippi reference soil (Karnac Ferry), respectively. Earthworm avoidance of contaminated soils was not observed in 48-h soil avoidance studies; however, isopods were shown to avoid food spiked with 12.7% by weight DU oxides through digital tracking studies. Environ Toxicol Chem © 2014 SETAC.

Concepts: Energy, Assessment, Toxicology, Toxicity, Depleted uranium, Aberdeen Proving Ground, Proving ground, Kinetic energy penetrator

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Acoustic sensors are being employed on airborne platforms for source localization. Under certain atmospheric conditions, airborne sensors offer a distinct advantage over ground sensors. Among other factors, the performance of airborne sensors is affected by refraction of sound signals due to vertical gradients in temperature and wind velocity. A comprehensive experiment in source localization with an aerostat-mounted acoustic system was carried out in July 2010 at Yuma Proving Ground (YPG). Acoustic sources on the ground consisted of one-pound TNT denotations and small arms firings. The height of the aerostat was approximately 1 km above the ground. In this paper, horizontal, azimuthal, and elevation errors in source localization and their statistics are studied in detail. Initially, straight-line propagation is assumed; then refraction corrections are introduced to improve source localization and decrease the errors. The corrections are based on a recently developed theory [Ostashev et al., J. Acoust. Soc. Am. (2008)] that accounts for sound refraction due to vertical profiles of temperature and wind velocity. During the 2010 YPG field test, the vertical profiles were measured only up to a height of approximately 100 m. Therefore, the European Center for Medium-range Weather Forecasts (ECMWF) is used to generate the profiles for July of 2010.

Concepts: Kilometre, Test method, Wind, Celestial coordinate system, Yuma, Arizona, Proving ground, Yuma Proving Ground, European Centre for Medium-Range Weather Forecasts