Download or read book Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long Term Plume Containment Task 4 written by Robert C. Starr and published by . This book was released on 2005 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trichloroethene (TCE), a common groundwater contaminant, can be degraded under certain conditions by microorganisms that occur naturally in the subsurface. TCE can be degraded under anaerobic conditions to less chlorinated compounds and ultimately into the non-chlorinated, non-hazardous end product, ethene, via anaerobic reductive dechlorination (ARD). ARD is widely recognized as a TCE degradation mechanism, and occurs in active groundwater remediation and can occur during monitored natural attenuation (MNA). MNA relies on natural processes, such as dispersion and degradation, to reduce contaminant concentrations to acceptable levels without active human intervention other than monitoring. TCE can also be biodegraded under aerobic conditions via cometabolism, in which microbial enzymes produced for other purposes fortuitously also react with TCE. In cometabolism, TCE is oxidized directly to non-hazardous products. Cometabolism as a TCE-degrading process under aerobic conditions is less well known than ARD. Natural attenuation is often discounted as a TCE remedial alternative in aerobic conditions based on the paradigm that TCE is biodegradable only under anaerobic conditions. In contrast to this paradigm, TCE was shown to degrade relative to conservative co-contaminants at an environmentally significant rate in a large (approximately 3 km long) TCE plume in aerobic groundwater at the Idaho National Laboratory (INL), and the degradation mechanism was shown to be cometabolism. MNA was selected as the remedy for most of this plume, resulting in a considerable cost savings relative to conventional remedial methods. To determine if cometabolism might be a viable remedy at other sites with TCE-contaminated aerobic groundwater, TCE plumes at Department of Energy (DOE) facilities were screened to evaluate whether TCE commonly degrades in aerobic groundwater, and if degradation rates are fast enough that natural attenuation could be a viable remedy. One hundred and twenty seven plumes at 24 DOE facilities were screened, and 14 plumes were selected for detailed examination. In the plumes selected for further study, spatial changes in the concentration of a conservative co-contaminant were used to compensate for the effects of mixing and temporal changes in TCE release from the contaminant source. Decline in TCE concentration along a flow path in excess of the co contaminant concentration decline was attributed to cometabolic degradation. This study indicated that TCE was degraded in 9 of the 14 plumes examined, with first order degradation half-lives ranging from about 1 to 12 years. TCE degradation in about two-thirds of the plumes examined suggests that cometabolism of TCE in aerobic groundwater is a common occurrence, in contrast to the conventional wisdom that TCE is recalcitrant in aerobic groundwater. The degradation half-life values calculated in this study are short enough that natural attenuation may be a viable remedy in many aerobic plumes. Computer modeling of groundwater flow and contaminant transport and degradation is frequently used to predict the evolution of groundwater plumes, and for evaluating natural attenuation and other remedial alternatives. An important aspect of a computer model is the mathematical approach for describing degradation kinetics. A common approach is to assume that degradation occurs as a first-order process. First order kinetics are easily incorporated into transport models and require only a single value (a degradation half-life) to describe reaction kinetics. The use of first order kinetics is justified in many cases because more elaborate kinetic equations often closely approximate first order kinetics under typical field conditions. A previous modeling study successfully simulated the INL TCE plume using first order degradation kinetics. TCE cometabolism is the result of TCE reacting with microbial enzymes that were produced for other purposes, such as oxidizing a growth substrate to obtain energy. Both TCE and the growth substrate compete for enzyme reactive sites, and the presence of one interferes with reactions with the enzyme by the other. It was assumed that a competitive inhibition kinetic expression would be more technically rigorous than a first order decay kinetic model. Two activities were undertaken to evaluate this assumption. First, a collaborator measured the parameters of this kinetic model under conditions similar to those of the INL TCE plume. The results will be used in a transport model to compare transport simulated using these measured values with transport simulated using kinetic parameter values from the literature, which are typically for actively growing microorganisms, in contrast to the steady-state, near starvation conditions in the INL TCE plume. Second, modification of flow and reactive transport simulation software to include a competitive inhibition kinetic model was begun.
Download or read book Cantus diversi Kyrie eleison Gloria in excelsis Credo in unum Deum Sanctus Agnus Ite missa est Pro singulis Solemnitatibus Dominicis Festis Feriis per Annum Additis etiam quatuor sequentiis Ex graduali Romano His accesserunt Antiphonae ad Processionem diei Purificationis Dominicae Palmarum decantandae Hymni ad processionem diei Corporis Christi Litaniae Majores in Rogationibus cum Exequiis Defunctorum Trois m thodes faciles pour apprendre le plein chant en peu de temps written by Claude Bachelu and published by . This book was released on 1697 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coupling of Realistic Rate Estimates with Genomics for Assessing Contaminant Attenuation and Long Term Plum Containment written by Ronald L. Crawford and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains a summary of progress of only Dr. Crawford's part of the effort. This part of the overall project involves examination of the microbial genomics of the Snake River Plain Aquifer (SRPA) at the INEEL Test Area North (TAN) site. The work is being performed by two graduate students, Mr. Daniel Erwin and Ms. Amy Torguson. Progress is reported here as work done by each student.
Download or read book Coupling of Realistic Real Estimates with Genomics for Assessing Contaminant Attenuation and Long Term Plume Containment written by Roland L. Crawford and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coupling of Realistic Real Estimates with Genomics for Assessing Contaminant Attenuation and Long-Term Plume Containment.
Download or read book Coupling of Realistic Rate Estimates with Genomic for Assessing Contaminant Attenuation and Long Term Phone written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dissolved dense nonaqueous-phase liquid plumes are persistent, widespread problems in the DOE complex. While perceived as being difficult to degrade, at the Idaho National Engineering and Environmental Laboratory, dissolved trichloroethylene (TCE) is disappearing from the Snake River Plain aquifer (SRPA) by natural attenuation, a finding that saves significant site restoration costs. Acceptance of monitored natural attenuation as a preferred treatment technology requires direct proof of the process and rate of the degradation. Our proposal aims to provide that proof for one such site by testing two hypotheses. First, we believe that realistic values for in situ rates of TCE cometabolism can be obtained by sustaining the putative microorganisms at the low catabolic activities consistent with aquifer conditions. Second, the patterns of functional gene expression evident in these communities under starvation conditions while carrying out TCE cometabolism can be used to diagnose the cometabolic activity in the aquifer itself. Using the cometabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained at this location and validate the long term stewardship of this plume. Realistic terms for cometabolism of TCE will provide marked improvements in DOE's ability to predict and monitor natural attenuation of chlorinated organics at other sites, increase the acceptability of this solution, and provide significant economic and health benefits through this noninvasive remediation strategy. Finally, this project will derive valuable genomic information about the functional attributes of subsurface microbial communities upon which DOE must depend to resolve some of its most difficult contamination issues.
Download or read book MASS BALANCE written by B. Looney and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Monitored natural attenuation (MNA) and enhanced attenuation (EA) are two environmental management strategies that rely on a variety of attenuation processes to degrade or immobilize contaminants and are implemented at appropriate sites by demonstrating that contaminant plumes have low risk and are stable or shrinking. The concept of a mass balance between the loading and attenuation of contaminants in a groundwater system is a powerful framework for conceptualizing and documenting the relative stability of a contaminant plume. As a result, this concept has significant potential to support appropriate implementation of monitored natural attenuation (MNA) and enhanced attenuation (EA). For mass balance to be useful in engineering practice, however, it is necessary to quantify it in practical ways that facilitate overall site remediation and which are consistent with existing regulatory guidance. Two divergent philosophies exist for quantifying plume stability--empirical and deterministic. The first relies on historical contaminant concentration data and bulk geochemical information from a monitoring well network and documents plume stability using trend analysis and statistical tools. This empirical approach, when feasible, provides powerful and compelling documentation of plume behavior and mass balance. It provides an interpretation on a relevant scale under field conditions. It integrates the operative attenuation processes measured by observing their actual impact on the plume. The power of the empirical approach was recognized early in the development of MNA guidance and protocols and it is currently the basis of the three lines of evidence used in MNA studies. The empirical approach has some weaknesses, however. It requires a relatively long period of undisturbed historical data. Thus it cannot be effectively applied to sites where active remediation was initiated quickly and is currently operating. It cannot be used as a tool to determine how much source removal is needed or when to turn off active remediation and transition to MNA. It cannot be used to evaluate potential enhancement options (unless a long period of post enhancement monitoring is planned). It provides only indirect information about process and treats the plume as a ''black box''. The empirical approach has the advantage that, when sufficient monitoring data are available, the attenuation capacity can be defined inexpensively and with a high degree of certainty. Alternatively, a deterministic approach can be used to assess mass balance and plume stability. In this approach, the physical, chemical, and biological attenuation processes are used to assess contaminant loading and attenuation. The deterministic approach has the advantage that, when sufficient hydrologic, geochemical, and microbiological data are available, it is possible to project how a system will respond to contaminant removal actions or enhancements of natural attenuation processes. The ''black box'' of the plume is taken apart, quantified, and put back together again. The disadvantage of the deterministic approach is that it is difficult to measure all or most of the relevant hydrologic, geochemical, and biological parameters with any certainty. Case studies over the past decade demonstrate that empirical and deterministic approaches to MNA/EA are not mutually exclusive. These studies document that improved decision support and efficiency result by combining these methods based on the individual challenges presented by a given site. Whenever possible, the empirical approach is used to quantify mass loading and attenuation capacity (mass of contaminant/unit time) at particular sites. This is the most effective way to demonstrate the efficiency of ongoing natural attenuation processes in accordance with current regulatory guidance. But in addition, the monitoring well networks needed to apply the empirical approach can also yield estimates of the hydrologic, geochemical, and biological parameters needed to apply deterministic models. These models can then be used to estimate how contaminant behavior will change over time, as contaminant mass is removed, or if attenuation mechanisms are enhanced by engineering methods. The dual use of these empirical and deterministic approaches can help integrate the use of MNA and EA for overall site remediation.
Download or read book Alternatives for Managing the Nation s Complex Contaminated Groundwater Sites written by National Research Council and published by National Academies Press. This book was released on 2013-02-27 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Across the United States, thousands of hazardous waste sites are contaminated with chemicals that prevent the underlying groundwater from meeting drinking water standards. These include Superfund sites and other facilities that handle and dispose of hazardous waste, active and inactive dry cleaners, and leaking underground storage tanks; many are at federal facilities such as military installations. While many sites have been closed over the past 30 years through cleanup programs run by the U.S. Department of Defense, the U.S. EPA, and other state and federal agencies, the remaining caseload is much more difficult to address because the nature of the contamination and subsurface conditions make it difficult to achieve drinking water standards in the affected groundwater. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites estimates that at least 126,000 sites across the U.S. still have contaminated groundwater, and their closure is expected to cost at least $110 billion to $127 billion. About 10 percent of these sites are considered "complex," meaning restoration is unlikely to be achieved in the next 50 to 100 years due to technological limitations. At sites where contaminant concentrations have plateaued at levels above cleanup goals despite active efforts, the report recommends evaluating whether the sites should transition to long-term management, where risks would be monitored and harmful exposures prevented, but at reduced costs.
Download or read book Guide to Best Practices for Ocean Acidification Research and Data Reporting written by and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitored Natural Attenuation of Inorganic Contaminants in Ground Water written by and published by . This book was released on 2007 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: V.3 ... consists of individual chapters that describe 1) the conceptual background for radionuclides, including tritium, radon, strontium, technetium, uranium, iodine, radium, thorium, cesium, plutonium-americium and 2) data requirements to be met during site characterization.
Download or read book Characterization Modeling Monitoring and Remediation of Fractured Rock written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2021-01-29 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractured rock is the host or foundation for innumerable engineered structures related to energy, water, waste, and transportation. Characterizing, modeling, and monitoring fractured rock sites is critical to the functioning of those infrastructure, as well as to optimizing resource recovery and contaminant management. Characterization, Modeling, Monitoring, and Remediation of Fractured Rock examines the state of practice and state of art in the characterization of fractured rock and the chemical and biological processes related to subsurface contaminant fate and transport. This report examines new developments, knowledge, and approaches to engineering at fractured rock sites since the publication of the 1996 National Research Council report Rock Fractures and Fluid Flow: Contemporary Understanding and Fluid Flow. Fundamental understanding of the physical nature of fractured rock has changed little since 1996, but many new characterization tools have been developed, and there is now greater appreciation for the importance of chemical and biological processes that can occur in the fractured rock environment. The findings of Characterization, Modeling, Monitoring, and Remediation of Fractured Rock can be applied to all types of engineered infrastructure, but especially to engineered repositories for buried or stored waste and to fractured rock sites that have been contaminated as a result of past disposal or other practices. The recommendations of this report are intended to help the practitioner, researcher, and decision maker take a more interdisciplinary approach to engineering in the fractured rock environment. This report describes how existing tools-some only recently developed-can be used to increase the accuracy and reliability of engineering design and management given the interacting forces of nature. With an interdisciplinary approach, it is possible to conceptualize and model the fractured rock environment with acceptable levels of uncertainty and reliability, and to design systems that maximize remediation and long-term performance. Better scientific understanding could inform regulations, policies, and implementation guidelines related to infrastructure development and operations. The recommendations for research and applications to enhance practice of this book make it a valuable resource for students and practitioners in this field.
Download or read book Responding to Oil Spills in the U S Arctic Marine Environment written by National Research Council and published by National Academies Press. This book was released on 2014-08-01 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: U.S. Arctic waters north of the Bering Strait and west of the Canadian border encompass a vast area that is usually ice covered for much of the year, but is increasingly experiencing longer periods and larger areas of open water due to climate change. Sparsely inhabited with a wide variety of ecosystems found nowhere else, this region is vulnerable to damage from human activities. As oil and gas, shipping, and tourism activities increase, the possibilities of an oil spill also increase. How can we best prepare to respond to such an event in this challenging environment? Responding to Oil Spills in the U.S. Arctic Marine Environment reviews the current state of the science regarding oil spill response and environmental assessment in the Arctic region north of the Bering Strait, with emphasis on the potential impacts in U.S. waters. This report describes the unique ecosystems and environment of the Arctic and makes recommendations to provide an effective response effort in these challenging conditions. According to Responding to Oil Spills in the U.S. Arctic Marine Environment, a full range of proven oil spill response technologies is needed in order to minimize the impacts on people and sensitive ecosystems. This report identifies key oil spill research priorities, critical data and monitoring needs, mitigation strategies, and important operational and logistical issues. The Arctic acts as an integrating, regulating, and mediating component of the physical, atmospheric and cryospheric systems that govern life on Earth. Not only does the Arctic serve as regulator of many of the Earth's large-scale systems and processes, but it is also an area where choices made have substantial impact on life and choices everywhere on planet Earth. This report's recommendations will assist environmentalists, industry, state and local policymakers, and anyone interested in the future of this special region to preserve and protect it from damaging oil spills.
Download or read book The Use of Dispersants in Marine Oil Spill Response written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-04-24 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whether the result of an oil well blowout, vessel collision or grounding, leaking pipeline, or other incident at sea, each marine oil spill will present unique circumstances and challenges. The oil type and properties, location, time of year, duration of spill, water depth, environmental conditions, affected biomes, potential human community impact, and available resources may vary significantly. Also, each spill may be governed by policy guidelines, such as those set forth in the National Response Plan, Regional Response Plans, or Area Contingency Plans. To respond effectively to the specific conditions presented during an oil spill, spill responders have used a variety of response optionsâ€"including mechanical recovery of oil using skimmers and booms, in situ burning of oil, monitored natural attenuation of oil, and dispersion of oil by chemical dispersants. Because each response method has advantages and disadvantages, it is important to understand specific scenarios where a net benefit may be achieved by using a particular tool or combination of tools. This report builds on two previous National Research Council reports on dispersant use to provide a current understanding of the state of science and to inform future marine oil spill response operations. The response to the 2010 Deepwater Horizon spill included an unprecedented use of dispersants via both surface application and subsea injection. The magnitude of the spill stimulated interest and funding for research on oil spill response, and dispersant use in particular. This study assesses the effects and efficacy of dispersants as an oil spill response tool and evaluates trade-offs associated with dispersant use.
Download or read book Chlorinated Solvent Source Zone Remediation written by Bernard H. Kueper and published by Springer Science & Business. This book was released on 2014-04-22 with total page 759 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is to help engineers and scientists better understand dense nonaqueous phase liquid (DNAPL) contamination of groundwater and the methods and technology used for characterization and remediation. Remediation of DNAPL source zones is very difficult and controversial and must be based on state-of-the-art knowledge of the behavior (transport and fate) of nonaqueous phase liquids in the subsurface and site specific geology, chemistry and hydrology. This volume is focused on the characterization and remediation of nonaqueous phase chlorinated solvents and it is hoped that mid-level engineers and scientists will find this book helpful in understanding the current state-of-practice of DNAPL source zone management and remediation.
Download or read book Negative Emissions Technologies and Reliable Sequestration written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-04-08 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: To achieve goals for climate and economic growth, "negative emissions technologies" (NETs) that remove and sequester carbon dioxide from the air will need to play a significant role in mitigating climate change. Unlike carbon capture and storage technologies that remove carbon dioxide emissions directly from large point sources such as coal power plants, NETs remove carbon dioxide directly from the atmosphere or enhance natural carbon sinks. Storing the carbon dioxide from NETs has the same impact on the atmosphere and climate as simultaneously preventing an equal amount of carbon dioxide from being emitted. Recent analyses found that deploying NETs may be less expensive and less disruptive than reducing some emissions, such as a substantial portion of agricultural and land-use emissions and some transportation emissions. In 2015, the National Academies published Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration, which described and initially assessed NETs and sequestration technologies. This report acknowledged the relative paucity of research on NETs and recommended development of a research agenda that covers all aspects of NETs from fundamental science to full-scale deployment. To address this need, Negative Emissions Technologies and Reliable Sequestration: A Research Agenda assesses the benefits, risks, and "sustainable scale potential" for NETs and sequestration. This report also defines the essential components of a research and development program, including its estimated costs and potential impact.
Download or read book The Precautionary Principle in the 20th Century written by Paul Harremoes and published by Routledge. This book was released on 2013-10-11 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: The precautionary principle is widely seen as fundamental to successful policies for sustainability. It has been cited in international courts and trade disputes between the USA and the EU, and invoked in a growing range of political debates. Understanding what it can and cannot achieve is therefore crucial. This volume looks back over the last century to examine the role the principle played or could have played, in a range of major and avoidable public disasters. From detailed investigation of how each disaster unfolded, what the impacts were and what measures were adopted, the authors draw lessons and establish criteria that could help to minimise the health and environmental risks of future technological, economic and policy innovations. This is an informative resource for all those from lawyers and policy-makers, to researchers and students needing to understand or apply the principle.
Download or read book Draft Toxicological Profile for Ethylbenzene written by and published by . This book was released on 2007 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.
