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Remediation Activities (remediation + activity)

Distribution by Scientific Domains

Earth and Environmental Science	62%

Selected Abstracts

Perimeter air monitoring for soil remediation

REMEDIATION, Issue 4 2007
Guy J. Graening
Most environmental project managers are well versed in characterizing and remediating contaminants in soil and water media. When soil remediation activities are conducted at an environmental site, however, some project managers are faced with monitoring contaminants in the air medium for the first time. Remediation activities can disturb contaminants that are normally immobile in soil and transfer them to air. The resulting increase in airborne concentrations of contaminants, even if temporary, may be a health concern for individuals in neighboring residences or businesses. Perimeter air monitoring may be required by a regulatory agency to determine if unhealthy conditions are created and if work practices should be limited or modified. This article serves as a resource for project managers involved in perimeter air monitoring for soil remediation and provides a general summary of candidate sites, remediation activities that release contaminants, regulatory requirements, equipment and target contaminants, monitoring locations and schedule, analytical methods, and data interpretation. © 2007 Wiley Periodicals, Inc. [source]

Copper toxicity thresholds for important restoration grass species of the western United States,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2002
Mark W.
Abstract Copper toxicity thresholds for plant species that are used in restoration activities in western North America have not been established. As a result, ecological risk assessments must rely on toxicity thresholds established for agronomic species, which usually differ from those of species used in restoration. Thus, risk assessors have the potential for classifying sites as phytotoxic to perennial, nonagronomic species and calling for intensive remediation activities that may not be necessary. The objective of this study was to provide a better estimate of Cu toxicity thresholds for five grass species that are commonly used in restoration efforts in the western United States. We used a greenhouse screening study where seedlings of introduced redtop (Agrostis gigantea Roth.), the native species slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners var. Pryor), tufted hairgrass (Deschampsia caespitosa [L.] Beauvois), big bluegrass (Poa secunda J. Presl var. Sherman), and basin wildrye (Leymus cinereus [Scribner&Merrill] A. Löve var. Magnar) and the agricultural species common wheat (Triticum aestivum L.) were grown in sand culture and exposed to supplemental concentrations of soluble Cu of 0 (control), 50, 100, 150, 200, 250, and 300 mg/L. We determined six measures of toxicity: the 60-d mean lethal concentration (LC50), 60-d mean effective concentration (EC50)-plant, 60-d EC50-shoot, 60-d EC50-root, phytotoxicity threshold (PT50)-shoot, and the PT50-root. Results suggest that these restoration grass species generally have higher Cu tolerance than agronomic species reported in the past. Of the species tested, redtop appeared to be especially tolerant of high levels of substrate and tissue Cu. Values of EC50-plant for restoration grasses were between 283 and 710 mg Cu/L compared to 120 mg Cu/L for common wheat. Measured PT50-shoot values were between 737 and 10,792 mg Cu/ L. These reported thresholds should be more useful for risk assessors than those currently used, which are based largely on agronomic crops. [source]

Validation of Numerical Ground Water Models Used to Guide Decision Making

GROUND WATER, Issue 2 2004
Ahmed E. Hassan
Many sites of ground water contamination rely heavily on complex numerical models of flow and transport to develop closure plans. This complexity has created a need for tools and approaches that can build confidence in model predictions and provide evidence that these predictions are sufficient for decision making. Confidence building is a long-term, iterative process and the author believes that this process should be termed model validation. Model validation is a process, not an end result. That is, the process of model validation cannot ensure acceptable prediction or quality of the model. Rather, it provides an important safeguard against faulty models or inadequately developed and tested models. If model results become the basis for decision making, then the validation process provides evidence that the model is valid for making decisions (not necessarily a true representation of reality). Validation, verification, and confirmation are concepts associated with ground water numerical models that not only do not represent established and generally accepted practices, but there is not even widespread agreement on the meaning of the terms as applied to models. This paper presents a review of model validation studies that pertain to ground water flow and transport modeling. Definitions, literature debates, previously proposed validation strategies, and conferences and symposia that focused on subsurface model validation are reviewed and discussed. The review is general and focuses on site-specific, predictive ground water models used for making decisions regarding remediation activities and site closure. The aim is to provide a reasonable starting point for hydrogeologists facing model validation for ground water systems, thus saving a significant amount of time, effort, and cost. This review is also aimed at reviving the issue of model validation in the hydrogeologic community and stimulating the thinking of researchers and practitioners to develop practical and efficient tools for evaluating and refining ground water predictive models. [source]

Initial results of remediation activities to restore hypereutrophic Villerest Reservoir (Roanne, France)

LAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2004
Louis-B.
Abstract We examined the impacts of remediation activities aimed at improving the water quality of hypereutrophic Villerest Reservoir, in which Microcystis aeruginosa dominated during the summer. We also compared nutrients and chlorophyll a data from this study with the results of a previous study on the reservoir. Between the two studies, the nitrogen and phosphorus loads into the reservoir from the main tributary decreased by 70% and 80%, respectively. Within the reservoir, the quantities of ammonia-nitrogen were similar in the two studies, and the total nitrogen was significantly higher in this study compared to the initial study. Both the phosphate-phosphorus and total phosphorus concentrations decreased significantly between the two studies. However, the statistically significant decrease in phosphate-phosphorus and total phosphorus did not always lead to a significant decrease in chlorophyll a concentrations. The nitrogen/phosphorus mass ratio during the present study remained well above five, the critical value below which summer blooms of Microcystis aeruginosa were observed in Villerest Reservoir. These study results indicated that the remediation activities being used to improve the water quality of Villerest Reservoir were off to a good start. [source]

Perimeter air monitoring for soil remediation

Poorly performing physicians: Does the script concordance test detect bad clinical reasoning?,

THE JOURNAL OF CONTINUING EDUCATION IN THE HEALTH PROFESSIONS, Issue 3 2010
François Goulet MD
Abstract Introduction Evaluation of poorly performing physicians is a worldwide concern for licensing bodies. The Collège des Médecins du Québec currently assesses the clinical competence of physicians previously identified with potential clinical competence difficulties through a day-long procedure called the Structured Oral Interview (SOI). Two peer physicians produce a qualitative report. In view of remediation activities and the potential for legal consequences, more information on the clinical reasoning process (CRP) and quantitative data on the quality of that process is needed. This study examines the Script Concordance Test (SCT), a tool that provides a standardized and objective measure of a specific dimension of CRP, clinical data interpretation (CDI), to determine whether it could be useful in that endeavor. Methods Over a 2-year period, 20 family physicians took, in addition to the SOI, a 1-hour paper-and-pencil SCT. Three evaluators, blind as to the purpose of the experiment, retrospectively reviewed SOI reports and were asked to estimate clinical reasoning quality. Subjects were classified into 2 groups (below and above median of the score distribution) for the 2 assessment methods. Agreement between classifications is estimated with the use of the Kappa coefficient. Results Intraclass correlation for SOI was 0.89. Cronbach alpha coefficient for the SCT was 0.90. Agreement between methods was found for 13 participants (Kappa: 0.30, P = 0.18), but 7 out of 20 participants were classified differently in both methods. All participants but 1 had SCT scores below 2 SD of panel mean, thus indicating serious deficiencies in CDI. Discussion The finding that the majority of the referred group did so poorly on CDI tasks has great interest for assessment as well as for remediation. In remediation of prescribing skills, adding SCT to SOI is useful for assessment of cognitive reasoning in poorly performing physicians. The structured oral interview should be improved with more precise reporting by those who assess the clinical reasoning process of examinees, and caution is recommended in interpreting SCT scores; they reflect only a part of the reasoning process. [source]