Long-Term Stabilization of Uranium By U(VI) Phosphate Mineralization in Weathered Bedrock and Soils Developed Over a Granite-Hosted Uranium Deposit

2002 ◽  
Vol 757 ◽  
Author(s):  
James L. Jerden ◽  
A. K. Sinha
Keyword(s):  
Vadose Zone ◽  
Mineralogical Characterization ◽  
Virginia Piedmont ◽  
The Us ◽  
Phosphate Mineralization ◽  
Us Epa ◽  
Mineral Coatings ◽  
Water Saturated

ABSTRACTThe unmined Coles Hill U deposit in the Virginia Piedmont represents a unique natural laboratory for studying the long-term containment of U by phosphate minerals. The primary ore assemblage consists of coffinite and apatite and is hosted in foliated granite. Geochemical and mineralogical studies of the weathered bedrock and soils developed over the primary ore body indicate that U transport is inhibited by the precipitation of meta-autunite group minerals. The lower part of the profile, which consists of ground water saturated saprolite, contains 1400 mg/kg U (in the solid). This concentration is 1.5 times greater than the mean ore grade of the deposit, indicating that the saprolites are enriched in U relative to the underlying primary ore. Uranium within the saprolite is dominantly associated with 10 to 500 μm long, tabular crystals of (Ba, Ca, Sr) meta-autunite. Ground waters from this zone contain less than 14 μg/L dissolved U suggesting that the U(VI) phosphate minerals present are capable of controlling dissolved U concentrations at values lower than the US-EPA maximum contaminant level (30 μg/L). Mineralogical characterization of the unsaturated soil horizons indicate that geochemical conditions in these zones are not conducive to U stabilization by meta-autunite mineralization. In the vadose zone U is primarily associated with Al phosphate (crandallite) and with P adsorbed or coprecipitated with iron oxide mineral coatings. Geochemical gradients suggest that significant amounts of U have been leached from the vadose zone by infiltrating fluids and reprecipitated below the water table, where the activity ratio of dissolved phosphate to carbonate increases. Based on regional weathering rates, the processes responsible for stabilization of U within the Coles Hill system are estimated to have been active for hundreds of thousands of years.

scholarly journals Characterization of atmospheric aerosol in the US Southeast from ground- and space-based measurements over the past decade

2011 ◽  
Vol 4 (6) ◽  
pp. 7559-7595
Author(s):  
E. J. Alston ◽  
I. N. Sokolik ◽  
O. V. Kalashnikova
Keyword(s):  
Regional Scale ◽  
Correlation Coefficients ◽  
The State ◽  
The Past ◽  
The Us ◽  
Us Epa ◽  
Terra Satellite ◽  
Strong Seasonality ◽  
Good Agreement

Abstract. This study examines how aerosols measured from the ground and space over the US Southeast change temporally over a regional scale during the past decade. PM2.5 data consist of two datasets that represent the measurements that are used for regulatory purposes by the US EPA and continuous measurements used for quickly disseminating air quality information. AOD data comes from three NASA sensors: the MODIS sensors onboard Terra and Aqua satellites and the MISR sensor onboard the Terra satellite. We analyze all available data over the state of Georgia from 2000–2009 of both types of aerosol data. The analysis reveals that during the summer the large metropolitan area of Atlanta has average PM2.5 concentrations that are 50% more than the remainder of the state. Strong seasonality is detected in both the AOD and PM2.5 datasets; as evidenced by a threefold increase of AOD from mean winter values to mean summer values, and the increase in PM2.5 concentrations is almost twofold from over the same period. Additionally, there is good agreement between MODIS and MISR onboard the Terra satellite during the spring and summer having correlation coefficients of 0.64 and 0.71, respectively. Monthly anomalies were used to determine the presence of a trend in all considered aerosol datasets. We found negative linear trends in both the monthly AOD anomalies from MODIS onboard Terra and the PM2.5 datasets, which are statistically significant for α = 0.05. Decreasing trends were also found for MISR onboard Terra and MODIS onboard Aqua, but those trends were not statistically significant.

scholarly journals SMOKE for Europe – adaptation, modification and evaluation of a comprehensive emission model for Europe

2010 ◽  
Vol 3 (3) ◽  
pp. 949-1007 ◽  
Author(s):  
J. Bieser ◽  
A. Aulinger ◽  
V. Matthias ◽  
M. Quante ◽  
P. Builtjes
Keyword(s):  
Emission Model ◽  
Transport Models ◽  
Emission Data ◽  
Criteria Pollutants ◽  
The Us ◽  
Spatially Distributed ◽  
Us Epa ◽  
Emission Models ◽  
Year 2000

Abstract. The US EPA regional emission model SMOKE was adopted and modified to create temporally and spatially distributed emission for Europe and surrounding countries based on official reports and public domain data only. The aim is to develop a flexible model capable of creating consistent high resolution emission data for long-term runs of Chemical Transport Models (CTM). This modified version of SMOKE, called SMOKE for EUROPE (SMOKE-EU) was successfully used to create hourly gridded emissions for the timespan 1970–2010. In this paper the SMOKE-EU model and the underlying European datasets are introduced. Emission data created by SMOKE-EU for the year 2000 are evaluated by comparison to data of three different state of the art emission models. Differences of SMOKE-EU to those models were in the same range as the differences amongst them. Further, concentrations of criteria pollutants calculated by the CTM CMAQ using the four different emission datasets were compared against EMEP measurements with hourly and daily resolution. Using SMOKE-EU emissions O3, NO2 and SO4 could be modelled most reliably. The amount of simulated concentrations within a factor of 2 (F2) of the observations for these species are: O3 (F2=0.79 N=329 197), NO2 (F2=0.55 N=11 465), and SO4 (F2=0.62 N=17 536). The lowest values were found for NH4 (F2=0.34 N=7400) and NO3 (F2=0.25 N=6184). NH4 concentrations were generally overestimated, leading to a fractional bias (FB) averaged over 22 measurement stations of (FB=0.83±0.41) while better agreements with observations were found for SO4 (FB=0.06±0.38, 51 stations) and NO3 (FB=0.13±0.75, 18 stations). CMAQ simulations using the three other emission datasets were similar to those modelled using SMOKE-EU emissions. Highest differences where found for NH4 while O3 concentrations were almost identical. The results of this comparison confirm that it is adequate to use emissions created by SMOKE-EU as input for CTMs.

scholarly journals Characterization of PAHs Trapped in the Soot from the Combustion of Various Mediterranean Species

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 965
Author(s):  
Valérie Leroy-Cancellieri ◽  
Dominique Cancellieri ◽  
Eric Leoni
Keyword(s):  
Human Health ◽  
Mutagenic Effect ◽  
Biomass Combustion ◽  
Health It ◽  
The Us ◽  
Source Organic Matter ◽  
Pahs Concentration ◽  
Carcinogenic Effects ◽  
Us Epa

Climate change causes more frequent and destructive wildfires even transforming them into megafire. Moreover, all biomass fires produce emissions of carbon compounds in the form of soot to the atmosphere with a significant impact on the environment and human health. Indeed, the soot is causing the formation of PAHs from (a) the high temperature thermal alteration of natural product precursors in the source organic matter and (b) the recombination of molecular fragments in the smoke. However, these molecules are known to have carcinogenic effects on human health. It is therefore interesting to quantify the 16 PAHs concentration extracted from soot emitted in open diffusion flame of biomass combustion. To achieve this objective, an analytical method developed for the study of kerosene combustion has been adapted for soot from biomass. This new method allowed to quantify the 16 PAHs defined as priority pollutants by the US EPA for their carcinogenic mutagenic effect and on human health.

scholarly journals Calcified Lesion Assessment and Intervention in Complex Percutaneous Coronary Intervention: Overview of Angioplasty, Atherectomy, and Lithotripsy

2020 ◽  
Vol 14 ◽  
Author(s):  
Alexander G Truesdell ◽  
Matheen A Khuddus ◽  
Sara C Martinez ◽  
Evan Shlofmitz
Keyword(s):  
Comprehensive Evaluation ◽  
Management Strategies ◽  
Coronary Intervention ◽  
Clinical Results ◽  
Calcified Lesion ◽  
Percutaneous Coronary ◽  
The Us ◽  
Artery Disease

Calcific coronary artery disease intervention is associated with uniformly worse short-term procedural and long-term clinical results compared with treatment of non-calcified lesions. Multiple intravascular imaging tools currently exist to aid the identification and detailed characterization of intracoronary calcium, and guide appropriate follow-on management strategies. Several unique device therapies, to include angioplasty, atherectomy, and lithotripsy may be employed to enhance lesion preparation, stent implantation and optimization, and improve patient outcomes. Current low use of both imaging and ablative technologies in the US offers significant future opportunities for improving the comprehensive evaluation and management of these complex lesion subsets and patients.

scholarly journals Long-term performance modelling of Etobicoke exfiltration system

2021 ◽  
Author(s):  
Haiyue Liu
Keyword(s):  
Stormwater Management ◽  
Low Impact Development ◽  
Hydrologic Cycle ◽  
Performance Modelling ◽  
The Us ◽  
Us Epa ◽  
Long Term Performance ◽  
Term Performance ◽  
The Impact

Urbanization increases the stress on the hydrologic cycle. The Etobicoke exfiltration system (EES) was developed in 1993 to remediate the impact on the hydrologic cycle after urbanization. The purpose of this research is to model the Etobicoke exfiltration system (EES) and evaluate the stormwater management performance of EES. A comprehensive literature review was conducted on development of stormwater management and Low impact development (LID). The US EPA SWMM was selected to model the EES. Three modelling methods were investigated to simulate the performance of EES. The Orifice-Storage-Pump method was found to perform the best. EES was applied before an existing wet pond in a case study subdivision. The modelling results show that EES meets three criteria: reduce water quantity, impact water balance and improve water quality.

scholarly journals SMOKE for Europe – adaptation, modification and evaluation of a comprehensive emission model for Europe

2011 ◽  
Vol 4 (1) ◽  
pp. 47-68 ◽  
Author(s):  
J. Bieser ◽  
A. Aulinger ◽  
V. Matthias ◽  
M. Quante ◽  
P. Builtjes
Keyword(s):  
Emission Model ◽  
Transport Models ◽  
Emission Data ◽  
Criteria Pollutants ◽  
The Us ◽  
Spatially Distributed ◽  
Us Epa ◽  
Emission Models ◽  
Year 2000

Abstract. The US EPA regional emission model SMOKE was adopted and modified to create temporally and spatially distributed emission for Europe and surrounding countries based on official reports and public domain data only. The aim is to develop a flexible model capable of creating consistent high resolution emission data for long-term runs of Chemical Transport Models (CTMs). This modified version of SMOKE, called SMOKE for EUROPE (SMOKE-EU) was successfully used to create hourly gridded emissions for the timespan 1970–2010. In this paper the SMOKE-EU model and the underlying European datasets are introduced. Emission data created by SMOKE-EU for the year 2000 are evaluated by comparison to data of three different state-of-the-art emission models. SMOKE-EU produced a range of values comparable to the other three datasets. Further, concentrations of criteria pollutants calculated by the CTM CMAQ using the four different emission datasets were compared against EMEP measurements with hourly and daily resolution. Using SMOKE-EU gave the most reliable modelling of O3, NO2 and SO42−. The amount of simulated concentrations within a factor of 2 (F2) of the observations for these species are: O3 (F2 = 0.79, N = 329 197), NO2 (F2 = 0.55, N = 11 465) and SO42− (F2 = 0.62, N = 17 536). The lowest values were found for NH4+ (F2 = 0.34, N = 7400) and NO3− (F2 = 0.25, N = 6184). NH4+ concentrations were generally overestimated, leading to a fractional bias (FB) averaged over 22 measurement stations of (FB = 0.83 ± 0.41) while better agreements with observations were found for SO42− (FB = 0.06 ± 0.38, 51 stations) and NO3− (FB = 0.13 ± 0.75, 18 stations). CMAQ simulations using the three other emission datasets were similar to those modelled using SMOKE-EU emissions. Highest differences where found for NH4+ while O3 concentrations were almost identical.

scholarly journals Characterization of atmospheric aerosol in the US Southeast from ground- and space-based measurements over the past decade

2012 ◽  
Vol 5 (7) ◽  
pp. 1667-1682 ◽  
Author(s):  
E. J. Alston ◽  
I. N. Sokolik ◽  
O. V. Kalashnikova
Keyword(s):  
Environmental Protection Agency ◽  
Regional Scale ◽  
Correlation Coefficients ◽  
The State ◽  
Study Region ◽  
The Past ◽  
The Us ◽  
Us Epa ◽  
Terra Satellite

Abstract. This study examines how aerosols measured from the ground and space over the US Southeast change temporally over a regional scale during the past decade. PM2.5 (particulate matter with aerodynamic diameter >2.5 micrometers) data consist of two datasets that represent the measurements that are used for regulatory purposes by the US EPA (Environmental Protection Agency) and continuous measurements used for quickly disseminating air quality information. AOD (aerosol optical depth) data come from three NASA sensors: the MODIS sensors onboard Terra and Aqua satellites and the MISR sensor onboard the Terra satellite. We analyze all available data over the state of Georgia from 2000–2009 of both types of aerosol data. The analysis reveals that during the summer the large metropolitan area of Atlanta has average PM2.5 concentrations that are 50% more than the remainder of the state. Strong seasonality is detected in both the AOD and PM2.5 datasets, as evidenced by a threefold increase of AOD from mean winter values to mean summer values, and the increase in PM2.5 concentrations is almost twofold over the same period. Additionally, there is agreement between MODIS and MISR onboard the Terra satellite during the spring and summer, having correlation coefficients of 0.64 and 0.71, respectively. Monthly anomalies were used to determine the presence of a trend in all considered aerosol datasets. We found negative linear trends for both the monthly AOD anomalies from MODIS onboard Terra and the PM2.5 datasets, which are statistically significant. Decreasing trends were also found for MISR onboard Terra and MODIS onboard Aqua, but those trends were not statistically significant. The observed decrease in AOD and PM2.5 concentrations may be indicative of the brightening over the study region during the past decade.

scholarly journals Long-term performance modelling of Etobicoke exfiltration system

2021 ◽  
Author(s):  
Haiyue Liu
Keyword(s):  
Stormwater Management ◽  
Low Impact Development ◽  
Hydrologic Cycle ◽  
Performance Modelling ◽  
The Us ◽  
Us Epa ◽  
Long Term Performance ◽  
Term Performance ◽  
The Impact

Urbanization increases the stress on the hydrologic cycle. The Etobicoke exfiltration system (EES) was developed in 1993 to remediate the impact on the hydrologic cycle after urbanization. The purpose of this research is to model the Etobicoke exfiltration system (EES) and evaluate the stormwater management performance of EES. A comprehensive literature review was conducted on development of stormwater management and Low impact development (LID). The US EPA SWMM was selected to model the EES. Three modelling methods were investigated to simulate the performance of EES. The Orifice-Storage-Pump method was found to perform the best. EES was applied before an existing wet pond in a case study subdivision. The modelling results show that EES meets three criteria: reduce water quantity, impact water balance and improve water quality.

Moving past the vaccine/autism controversy - to examine potential vaccine neurological harms

2020 ◽  
pp. 1-15
Author(s):  
Peter R. Breggin
Keyword(s):  
Neurological Disorders ◽  
Developmental Disorder ◽  
Physical Symptoms ◽  
Psychosocial Disorders ◽  
The Us ◽  
Potential Vaccine ◽  
Research And Education ◽  
The Brain ◽  
New Vaccines

BACKGROUND: The vaccine/autism controversy has caused vast scientific and public confusion, and it has set back research and education into genuine vaccine-induced neurological disorders. The great strawman of autism has been so emphasized by the vaccine industry that it, and it alone, often appears in authoritative discussions of adverse effects of the MMR and other vaccines. By dismissing the chimerical vaccine/autism controversy, vaccine defenders often dismiss all genuinely neurological aftereffects of the MMR (measles, mumps, and rubella) and other vaccines, including well-documented events, such as relatively rare cases of encephalopathy and encephalitis. OBJECTIVE: This report explains that autism is not a physical or neurological disorder. It is not caused by injury or disease of the brain. It is a developmental disorder that has no physical origins and no physical symptoms. It is extremely unlikely that vaccines are causing autism; but it is extremely likely that they are causing more neurological damage than currently appreciated, some of it resulting in psychosocial disabilities that can be confused with autism and other psychosocial disorders. This confusion between a developmental, psychosocial disorder and a physical neurological disease has played into the hands of interest groups who want to deny that vaccines have any neurological and associated neuropsychiatric effects. METHODS: A review of the scientific literature, textbooks, and related media commentary is integrated with basic clinical knowledge. RESULTS: This report shows how scientific sources have used the vaccine/autism controversy to avoid dealing with genuine neurological risks associated with vaccines and summarizes evidence that vaccines, including the MMR, can cause serious neurological disorders. Manufacturers have been allowed by the US Food and Drug Administration (FDA) to gain vaccine approval without placebo-controlled clinical trials. CONCLUSIONS: The misleading vaccine autism controversy must be set aside in favor of examining actual neurological harms associated with vaccines, including building on existing research that has been ignored. Manufacturers of vaccines must be required to conduct placebo-controlled clinical studies for existing vaccines and for government approval of new vaccines. Many probable or confirmed neurological adverse events occur within a few days or weeks after immunization and could be detected if the trials were sufficiently large. Contrary to current opinion, large, long-term placebo-controlled trials of existing and new vaccines would be relatively easy and safe to conduct.

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