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Environmental Release (environmental + release)
Selected AbstractsStable implantation of orthogonal sensor circuits in Gram-negative bacteria for environmental releaseENVIRONMENTAL MICROBIOLOGY, Issue 12 2008Aitor De Las Heras Summary A broad host range, orthogonal genetic platform has been developed to format sensor circuits in the chromosome of Gram-negative microorganisms destined for environmental release as bioindicators of toxic or perilous compounds (e.g. explosives) in soil. The genetic scheme includes the generation of a genomic landing pad for the sensor module with a Tn5 -mini-transposon bearing an optimal attTn7 sequence and a choice of reporter systems with optical and enzymatic outputs. The array of functional elements thereby inserted in the chromosome match that of a cognate plasmid vector which delivers the transcription factors and the promoters to a frame that places the regulatory parts in front of the reporters. Site-specific recombination sites allow the deletion of antibiotic resistances and enables reporter output prior to deliberate release. The system thus allows the production and maintenance of cells in a pre-release state and its intentional conversion in deliverable strains that fulfil all safety, stability and performance criteria. The combination of such a genetic platform with a variant of the transcriptional regulator XylR of Pseudomonas putida that responds to 2,4-dinitrotoluene has been the basis for the production of strains that emit light upon exposure to residues of explosives in a soil microcosm. [source] Evaluation of Bioaccumulation Using In Vivo Laboratory and Field Studies,INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2009Annie V Weisbrod Abstract A primary consideration in the evaluation of chemicals is the potential for substances to be absorbed and retained in an organism's tissues (i.e., bioaccumulated) at concentrations sufficient to pose health concerns. Substances that exhibit properties that enable biomagnification in the food chain (i.e., amplification of tissue concentrations at successive trophic levels) are of particular concern due to the elevated long-term exposures these substances pose to higher trophic organisms, including humans. Historically, biomarkers of in vivo chemical exposure (e.g., eggshell thinning, bill deformities) retrospectively led to the identification of such compounds, which were later categorized as persistent organic pollutants. Today, multiple bioaccumulation metrics are available to quantitatively assess the bioaccumulation potential of new and existing chemicals and identify substances that, upon or before environmental release, may be characterized as persistent organic pollutants. This paper reviews the various in vivo measurement approaches that can be used to assess the bioaccumulation of chemicals in aquatic or terrestrial species using laboratory-exposed, field-deployed, or collected organisms. Important issues associated with laboratory measurements of bioaccumulation include appropriate test species selection, test chemical dosing methods, exposure duration, and chemical and statistical analyses. Measuring bioaccumulation at a particular field site requires consideration of which test species to use and whether to examine natural populations or to use field-deployed populations. Both laboratory and field methods also require reliable determination of chemical concentrations in exposure media of interest (i.e., water, sediment, food or prey, etc.), accumulated body residues, or both. The advantages and disadvantages of various laboratory and field bioaccumulation metrics for assessing biomagnification potential in aquatic or terrestrial food chains are discussed. Guidance is provided on how to consider the uncertainty in these metrics and develop a weight-of-evidence evaluation that supports technically sound and consistent persistent organic pollutant and persistent, bioaccumulative, and toxic chemical identification. Based on the bioaccumulation information shared in 8 draft risk profiles submitted for review under the United Nations Stockholm Convention, recommendations are given for the information that is most critical to aid transparency and consistency in decision making. [source] Reactive chemicals emergency response and post-event calorimetric testingPROCESS SAFETY PROGRESS, Issue 1 2010David Frurip Abstract A serious upset in process conditions may result in a Reactive Chemicals incident. In such an emergency, procedures must be implemented to prevent injuries, mitigate the event and minimize property loss and/or environmental release as dictated by the required facility Emergency Plan. This article describes the process the Dow Chemical Company uses for engaging Reactive Chemicals experts in an emergency situation. In order to be effective, the Reactive Chemicals expert must have or be provided with in-depth knowledge of the process streams and raw materials involved. The information is crucial for understanding what is happening, what might happen in the immediate future, and what can be done to successfully mitigate the Reactive Chemicals incident. Following the incident, calorimetric experiments are typically performed to confirm or refute the hypotheses of what caused the event; additionally, the experiments provide information as to reactive chemicals hazards that may potentially still exist in the process streams. The aforementioned process will be illustrated by describing an actual event. Useful methods are described and recommended for (a) characterizing and storing reactive chemicals, and (b) responding and mitigating safety incidents with reactive chemicals. The role of a reactive chemicals "expert" during and after a plant emergency is important and potentially critical to the safe handling of an ongoing event and also in determining the root cause of the incident. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2010 [source] Suicidal genetically engineered microorganisms for bioremediation: Need and perspectivesBIOESSAYS, Issue 5 2005Debarati Paul In the past few decades, increased awareness of environmental pollution has led to the exploitation of microbial metabolic potential in the construction of several genetically engineered microorganisms (GEMs) for bioremediation purposes. At the same time, environmental concerns and regulatory constraints have limited the in situ application of GEMs, the ultimate objective behind their development. In order to address the anticipated risks due to the uncontrolled survival/dispersal of GEMs or recombinant plasmids into the environment, some attempts have been made to construct systems that would contain the released organisms. This article discusses the designing of safer genetically engineered organisms for environmental release with specific emphasis on the use of bacterial plasmid addiction systems to limit their survival thus minimizing the anticipated risk. We also conceptualize a novel strategy to construct "Suicidal Genetically Engineered Microorganisms (SGEMs)" by exploring/combining the knowledge of different plasmid addiction systems (such as antisense RNA-regulated plasmid addiction, proteic plasmid addiction etc.) and inducible degradative operons of bacteria. BioEssays 27:563,573, 2005. © 2005 Wiley Periodicals, Inc. [source] Recombinant bacteria for environmental release: what went wrong and what we have learnt from itCLINICAL MICROBIOLOGY AND INFECTION, Issue 2009V. De Lorenzo Abstract From a biotechnological point of view, bacteria can be seen as either pathogens to target with new drugs or as biocatalysts for large-scale processes in industry, agriculture or the environment. The last includes the exploitation of bacterial activities for bioremediation of toxic waste either in situ or ex situ. The onset of genetic engineering in the late 70s opened the possibility of tailoring recombinant bacteria for environmental release, aimed at biodegradation of otherwise recalcitrant chemicals. However, a few decades later the outcome of this prospect has been quite meager. The literature counts very few cases where the use of genetically engineered bacteria has been proven to be more efficient than natural microorganisms in elimination of recalcitrant compounds under natural (not laboratory) conditions. Fortunately, the emergence of Systems and Synthetic Biology in the last few years is helping to identify what were the caveats of the former approaches and how to correct them. In addition, robust design concepts imported from process engineering provides fresh approaches to the challenge of designing microorganisms á la carte for environmental applications. [source] Modelling ecological half-lives for radiocaesium in Norwegian brown trout populationsJOURNAL OF APPLIED ECOLOGY, Issue 1 2000Dag O. Hessen Summary 1.,Models of ecological half-life may be valuable and cost-effective predictive tools for authorities setting restrictions on human consumption of freshwater fish after environmental releases of radioactivity. This work aimed to validate such a model for radioactive caesium (134Cs and 137Cs) in brown trout Salmo trutta populations. Data were drawn from lakes with a wide variability in abiotic and biotic factors and initial caesium load. 2.,In Norway, the highest fallout (more than 150 kBq m,2 of 137Cs) from the Chernobyl accident occurred in Oppland county, in south central Norway. Radioactivity was measured in more than 1800 samples of brown trout in nearly 100 localities in this region during 1986,95. 3.,The back-calculated maximum initial radioactivity on 1 January 1987 showed a strong regional variability (range 443,13 370; average 3855 Bq kg,1). Large variation in initial radioactivity was also recorded on a local scale (within 50 km). 4.,The ecological half-life model for caesium in brown trout populations for 1987,94/95 gave a close fit to real data from all localities with sufficient time series. Predicted half-lives ranged from 1·2 to 4·2 years (average 2·5) but 95% confidence limits were narrow (2·7 and 2·3 years). 5.,The overall variability in radioactivity levels over time was almost entirely related to the initial load and, with few exceptions, 88% of the changes in radioactivity was explained by the simple regression model. Modest variability in ecological half-life was not correlated with initial activity, and no clear effects of water quality or season could be detected. For most lakes, levels of radioactivity in brown trout appeared to be predictable, with high accuracy after a fallout event, without extensive information on population ecology and water quality. However, more detailed work may be required to assess patterns within individual lakes. [source] Substance Flow Analysis of Mercury Intentionally Used in Products in the United StatesJOURNAL OF INDUSTRIAL ECOLOGY, Issue 3 2007Alexis Cain Mercury-containing products release mercury (Hg) throughout their lifecycles, frequently in ways that are difficult to measure directly. Therefore, there are considerable uncertainties about the magnitude of mercury releases associated with products, about which products and which release pathways contribute the most to mercury releases, and about the likely impact on mercury releases of various possible interventions in the mercury content of products or in the management of mercury-containing wastes. This article presents an effort to use substance flow analysis to develop improved estimates of the environmental releases caused by mercury-containing products and to provide policy-makers with a better understanding of opportunities for reducing releases of mercury caused by products. [source] Characterizing, Propagating, and Analyzing Uncertainty in Life-Cycle Assessment: A Survey of Quantitative ApproachesJOURNAL OF INDUSTRIAL ECOLOGY, Issue 1 2007Shannon M. Lloyd Summary Life-cycle assessment (LCA) practitioners build models to quantify resource consumption, environmental releases, and potential environmental and human health impacts of product systems. Most often, practitioners define a model structure, assign a single value to each parameter, and build deterministic models to approximate environmental outcomes. This approach fails to capture the variability and uncertainty inherent in LCA. To make good decisions, decision makers need to understand the uncertainty in and divergence between LCA outcomes for different product systems. Several approaches for conducting LCA under uncertainty have been proposed and implemented. For example, Monte Carlo simulation and fuzzy set theory have been applied in a limited number of LCA studies. These approaches are well understood and are generally accepted in quantitative decision analysis. But they do not guarantee reliable outcomes. A survey of approaches used to incorporate quantitative uncertainty analysis into LCA is presented. The suitability of each approach for providing reliable outcomes and enabling better decisions is discussed. Approaches that may lead to overconfident or unreliable results are discussed and guidance for improving uncertainty analysis in LCA is provided. [source] | ||||||||||