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Although evasion of elemental mercury from aquatic systems can significantly deplete net mercury accumulation resulting from atmospheric deposition, the current ability to model elemental mercury air/water exchange is limited by uncertainties in our understanding of all gaseous a...

The experimental proton affinity of diborane (B2H6) is based on an unstable species, B2H,+, 4 which has been observed only at low temperatures. The present work calculates the proton 5 affinity of diborane using the Gaussian-3 method and other high-level compound ab initio 6 met...

A mechanistic model to predict the capture of gas phase mercury species using in-situ generated titania nanosize particles activated by UV irradiation is developed. The model is an extension of a recently reported model1 for photochemical reactions that accounts for the rates of...

A New High Resolution Mass Spectrometry Technique for Identifying Pharmaceuticals and Potential Endocrine Disruptors in Drinking Water Sources <br><br>Andrew H. Grange and G. Wayne Sovocool U.S.EPA, ORD, NERL, ESD, ECB, P.O. Box 93478, Las Vegas, NV 891933478 <br><br>Mass spectra...

It is well known that mercury (Hg) cycles through air, water and soil on a global scale. Global-scale modeling of atmospheric Hg has encountered challenges. Relatively coarse spatial discretization is needed to achieve global coverage without incurring excessive computational c...

Persistent organic pollutants and mercury are likely to bioaccumulate in biological components of the environment, including fish and wildlife. The complex and long-term dynamics involved with bioaccumulation are often represented with models. Current scientific developments in t...

A panel of international experts was convened in Madison, Wisconsin, in 2005 as part of the 8th International Conference on Mercury as a Global Pollutant. Our charge was to address the state of science pertinent to source attribution; specifically our key question was "For a give...

We demonstrate a spatially-explicit regional assessment of current condition of aquatic ecoservices in the Coal River Basin (CRB), with limited sensitivity analysis for the atmospheric contaminant mercury. The integrated modeling framework (IMF) forecasts water quality and quant...

The U.S. EPA conducted a national statistical survey of fish fillet tissue with a sample size of 541 sites on boatable rivers =>5th order in 2008–2009. This is the first such study of mercury (Hg) in fish tissue from river sites focused on potential impacts to human health from f...

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This work defines several factors influencing the methylation of mercuric ion in soil. Two of the most important findings were that it is possible to extract the mercury methylating factor from soil with a solution of 0.5N sodium hydroxide and that this factor is responsible for ...

Public concern over cleanliness and safety of source and recreational waters has prompted researchers to look for indicators of water quality. Giving public water authorities multiple tools to measure and monitor levels of chemical contaminants, as well as chemical markers of c...

The Office of Solid Waste and Emergency Response (OSWER) has identified the development of improved methods for measuring, monitoring, and characterizing complex wastes in soils, sediments, biota, and groundwater as a priority under GOAL 3: LAND PRESERVATION AND RESTORATION:Prese...

A full assessment of the impact of the release of air toxic compounds into the atmosphere requires a detailed understanding of their atmospheres lifetimes and fates. The objective of this task is to begin to develop such data for the 33 classes of air toxic compounds identified ...

This research focuses on developing models that can describe the chemical and physical processes affecting concentrations of toxic air pollutants in the atmosphere, at spatial scales, ranging from local (< 1 km) to regional (36 km). One objective of this task is to extend the ca...

This is the first phase of a potentially multi-phase project aimed at identifying scientific methodologies that will lead to the development of innnovative analytical tools supporting the analysis of control strategy effectiveness, namely. accountabilty. Significant reductions i...

The trend towards episodic modeling of environmentally-dependent emissions is increasing, with models available or under development for dust, ammonia, biogenic volatile organic compounds, soil nitrous oxide, pesticides, sea salt, and chloride, mercury, and wildfire emissions. T...

There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

Monomethylmercury (CH3Hg+) is both the most ecologically significant and the least well characterized species of mercury in environmental settings. Our understanding of the environmental speciation behavior of this compound is limited both as the result of lesser available labor...

CEMs - Tekran Instrument Corp. Series 3300 and Thermo Electron's Mercury Freedom System Continuous Emission Monitors (CEMs) for mercury are designed to determine total and/or chemically speciated vapor-phase mercury in combustion emissions. Performance for mercury CEMs are cont...

Zwitterions are aqueous solvated molecules simultaneously possessing one negatively and one positively charged site. Although electroneutral, the environmental interaction of zwitterions with other ionic species is likely to differ significantly from the behavior of comparable e...

There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

Using atmospheric transport and fate models, it has been possible to link the changes in emissions to to the change in atmospheric deposition for the last thirty years for the criteria air pollutants, but it has only been in the last decade that advances have been made to allow t...

The National Human Exposure Assessment Survey (NHEXAS) was developed as a federal interagency research effort to examine the full range of environmental pollutants and chemicals (volatile organic chemicals, metals, and pesticides) that humans are exposed to in daily life. The pu...

This paper describes the method development for the determination of ultra-low level pesticides from high-elevation lake waters by large-volume injection programmable temperature vaporizer (LVI-PTV) GC/MS. This analytical method is developed as a subtask of a larger study, backgr...