Filters: Tags: Organic compounds (X) > Extensions: Project (X)
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Much work has been done to track spilled oil and study its fate and its effect on the environment. Our studies involved developing and applying methods to identify and track spilled oil as it weathers, as well as to differentiate it from other petrogenic hydrocarbon input sources, as well as differentiating petrogenic sources. This work in identifying petroleum sources, both natural and anthropogenic, has a great deal of transfer value to other estuarine systems.
Organic substances in streams affect the water quality and uses of the water. To determine the effect of organic substances on water quality, the physical, chemical, and biological processes involved in the transport and degradation of these substances must be understood. Procedures for measuring or estimating the rate coefficients describing these processes must be developed. Models using these coefficients must then be developed for predicting the fate of organic substances in streams and their effect on water quality. Project objectives are: (1) to study the fundamentals of volatilization, dispersion, and sorption on sediments of organic substances in water; (2) to develop sub-models of these processes including...
Categories: Project;
Tags: Organic Compounds
Humic substances are the predominant form of natural organic matter (NOM) in soil and water and comprise the major pools of biologically refractory organic carbon and nitrogen in the biosphere. Humic substances play a role in almost all geochemical processes affecting soil and water. Knowledge of the formation and mineralization pathways of soil and aquatic humic substances is therefore critical to an understanding of the biogeochemical cycles of carbon and nitrogen, and climate change. Humic substances act as electron donor-acceptor systems and thus participate in oxidation –reduction processes with transition metal ions and biological systems in soil and water environments. Chlorination and chloramination of...
Aquatic humic substances and other classes of dissolved organic material present in natural waters can control the biogeochemistry of trace metals and other solutes and can influence ecological processes in lakes and streams. The nature and reactivity of the dissolved organic material is in turn influenced by biological, chemical, and physical processes occurring in the aquatic environment. Recent advances in isolating and characterizing different fractions of the dissoloved organic carbon (DOC) and in measuring rates of microbial processes can be used to advance the understanding of the dynamic relationship between aquatic biota and dissolved organic material and trace metals in different environments. Project...
I conduct research on the transport and fate of organic contaminants in aquatic systems (terrestrial and marine). This entails field investigations and laboratory experiments that are designed to advance our understanding of natural processes and the effects of these processes on the behavior, mobility, and geochemical fate of organic chemicals of concern. I develop and apply new sampling and analytical techniques, identify potential molecular tracers, and develop models to predict contaminant fate. The laboratory I supervise houses analytical instrumentation that is used for detailed characterization of complex mixtures of organic chemicals as well as quantitative determination of targeted substances at ultra-trace...
The overall objective of this project is to determine the role of chemical processes associated with dissolved organic carbon (DOC) on the transport and reactivity of both naturally occurring and anthropogenic compounds. Defining the roles of DOC in environmental and geochemical processes is critical to understanding the nature and quality of the Nation’s water resources, and is important for future management of these resources. This field of study has increased in relevancy as numerous environmental problems have been linked to processes involving organic matter. My project attempts to meet these needs by focusing on the chemical mechanisms controlling the fate, transport, and reactivity of naturally occurring...
Many persistent organic compounds are hazardous to human and ecological health. The transport characteristics of these compounds across environmental phases are strongly influenced by adsorption and partition interactions with the individual phases. Quantification of process rates and partition constants of organic pollutants in air, water, soil, and biota is an important step in defining the level of organic contaminants in environmental systems and their potential impact on environmental quality. Project objectives are to delineate and quantify processes affecting the movement and distribution of persistent organic compounds in hydrogeologic systems. Specifically: (1) determine the sorptive capacity of soil and...
Delineate and quantify processes affecting the movement and distribution of pollutants in hydrogeologic systems. (1) Determine the sorptive capacity of soil and sediment for compounds of interest that are dissolved in water; (2) identify the roles of soil and sediment organic matter and mineral components in sorption of pollutants; (3) examine the interaction of natural organic matter with mineral surfaces and its consequent effect on sorption of compounds of interest; (4) characterize the effect of dissolved organic matter on the solubility and mobility of organic contaminants in natural water; and (5) determine the characteristics of pyrogenic soil components (black carbon) and its effects on fate and transport...
There is a general lack of knowledge of fundamental processes governing the fate and transport of anthropogenic organic compounds in surface and ground waters. Interactions of organic contaminants with natural organic coatings on sediments and aquifer porous media are not well understood. Furthermore, abiotic and biological transformations of organic contaminants in surface and ground waters require extensive fundamental investigations if their effects on Water Quality are to be understood. Objectives are to (1) determine physicochemical and biological processes, controlling the fate and transport of organic compounds in surface and ground waters; (2) determine bioavailability of hydrophobic organic contaminants...
Categories: Project;
Tags: Groundwater Flow and Transport,
Organic Compounds,
Surface-Water Transport and Reactions
The overall objective of this project is to determine the nature of natural organic carbon and organic nitrogen during its biogeochemical cycling through the environment and its interactions with anthropogenic compounds. Emerging techniques in liquid chromatography/mass spectrometry, liquid chromatography/tandem mass spectrometry, infrared spectroscopy and other means will be used to gain new insights into dominant processes responsible for fate, transport, and reactivity. Field- and laboratory-based experiments will enable direct application to current environmental problems such as disinfection byproduct formation potential, long-term effects of forest fires, and sustainability of agricultural soils. The chemical,...
Categories: Project;
Tags: Carbon Cycling and Sequestration,
Contaminants,
Nitrogen Cycling,
Organic Compounds
Natural organic polyelectrolytes are highly active materials that are present in practically all natural water systems. They interact with both organic and inorganic pollutants and nutrients, influencing, and in many instances, controlling the toxicity, rate of movement, persistence and rate of degradation of the pollutants and nutrients in aquatic environments. Detailed knowledge of the chemistry of natural organic polyelectrolytes is therefore of primary importance in understanding the chemical changes that affect all of the components of natural water systems. Organic polyelectrolytes are partially eliminated from drinking water by coagulation and chlorination; however, the products of chlorination are not known....
Degradation of organic material produces organic compounds that both alter the quality of water and affect the inorganic reactions. The hydrogeologic controls on organic-inorganic reactions, their rate, and progress are not well understood. This project focuses on the occurrence and fate of organic compounds in (1) contaminant aquifers, (2) soils, and (3) lake sediments. Project objectives are to increase our understanding of reactions involving organic matter and to evaluate the significance of these reactions in geochemical studies. Of particular interest are: identifying organic and inorganic compounds that are present as a result of the degradation of organic material; studying the interaction of organic compounds...
A disproportionate amount of research in water chemistry has been directed towards defining trace levels of organic contaminants in water whereas the structures and characteristics of natural organic substances, in the dissolved, suspended, and bed sediment phases, are very poorly understood. A better knowledge of the nature of natural organic substances in water is essential to the advancement of many diverse sciences, such as organic geochemistry, aquatic biology, soil science, hydrology involving contaminant transport, and even atmospheric chemistry involving carbon cycle research. The Water Resources Division is conducting significant research on the nature of humic substances in water, which comprise less than...
Categories: Project;
Tags: Organic Compounds
Greater than 90 percent of the organic solutes in water are of natural origin, yet little is known about the chemistry or source of these organic materials. However, these substances are known to complex trace metals, to transport pesticides, to be precursors of carcinogen compounds upon chlorination, and to be a food source for aquatic organisms. These processes need further clarification and quantification. The overall objectives are to quantify and to identify organic solutes that affect water quality processes. Specific objectives are: (1) to measure the amount of different organic solutes in various hydrologic environments; (2) to understand the origin, structure, and reactivity of aquatic humic substances;...
Categories: Project;
Tags: Organic Compounds
Release of various synthetic organic compounds to the environment has caused soil and ground-water pollution in many places. The processes which control the persistence and movement of these materials are not well understood. A better understanding is necessary to aid in construction of models to predict movement and fate of pollutants in the subsurface and for design of control and abatement techniques. Project objectives are to determine the transformation pathways of selected organic compounds using a combination of field observations and laboratory simulations of environmental conditions; assess the relative importance of physical, chemical, and biochemical processes in the transformation of these compounds...
Categories: Project;
Tags: Organic Compounds
I conduct long-term investigations on the fate and geochemical effect of organic contaminants in subsurface environments. I use a combined field and laboratory approach in a variety of hydrogeologic environments in order to meet these objectives. The principal questions being addressed by this project are: 1. How do long-term changes in biogeochemical processes affect the fate of organic and inorganic constituents in aquatic environments? and 2. Does availability of electron acceptors and electron donors control the progress of degradation reactions? My overarching objective is to increase our understanding of the transformation of contaminants from hydrocarbon spills, wastewaters from oil and gas development,...
The intrusion of industrial, agricultural and domestically produced organic chemicals and wastes into the aquatic environment is a well known reality and is considered to be one of the most important environmental problems. The widespread finding of these anthroprogenic substances, in addition to naturally occurring organics, and their detrimental impact on the Nation's water resources points to our need to understand how these substances act and react in the environment. Knowledge of transport, persistence, transformation, solubility, sorption, and reaction kinetics is needed to determine the fate of the substances in the hydrosphere. Objectives of project are to (1) identify organic substances associated with...
My research program is multifaceted and involves the development of integrated hydrological, geochemical, and biological knowledge on the source-to-receptor approach to assessing impacts of emerging contaminants (hormones, personal care products, pharmaceuticals, commercial cleaning products). This applied research is targeted on issues important to water-resource managers and policy makers, and the results communicated to a spectrum of stakeholders. The current focus of my research is the impact of biologically-active contaminants on aquatic organisms, and the relationship to receiving water (surface water and groundwater) attenuation capacity. Several major classes of contaminants are being investigated – endocrine...
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