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1.
Simple mathematical models are developed to account for the rather slow mass transport of nonaqueous phase liquid (NAPL) into aqueous solution in groundwater during flushing operations. The models are based on the assumption that this bottleneck in the process is associated with diffusion in the aqueous phase in the porous medium from the location of the NAPL drops/ganglia in a region of relatively low permeability out into a region of substantially higher permeability, somewhat analogous to diffusion from a block of porous rock into a nearby fracture, where the fracture system overwhelmingly dominates the overall permeability. The models include batch flushing, flushing in a laboratory column, and a one-dimensional model for flushing by means of a single recovery well.  相似文献   
2.
Worldwide, agencies with high levels of contamination are faced with decisions about remediation and restoration. These decisions should be informed by future land use and long‐term stewardship goals. In the United States, the Department of Energy has lands in some 34 states that require cleanup. They are involved in massive remediation and restoration efforts on lands from the Cold War legacy and wish to reduce their overall footprint. Understanding future land use preferences is essential for determining the nature and degree of remediation and restoration. The objective of this study was to examine future land use preferences for the Department of Energy's Los Alamos National Laboratory as a function of ethnicity for attendees at the Los Alamos Gun Show in New Mexico (1999), and to determine whether their own activity influences future land use preferences. The highest preferred future land uses for Los Alamos National Laboratory were hiking, camping, National Environmental Research Park, and birdwatching, followed by hunting and fishing. Increased nuclear waste storage and building homes and factories were rated the lowest. Further, hiking and camping were rated higher than at two other DOE sites. There were few ethnic differences, although American Indians rated camping, hiking, building houses, and returning the land to American Indians higher than did others, and Hispanics rated using it for a preserve as a higher preferred land use than all others. The differences, however, were not great. Relative ratings for using the land for hunting and fishing were directly related to individual frequency of hunting and fishing for both whites and Hispanics, indicating that people perceive the importance of land use by how they want to use it. Ratings for hiking and camping were not related to the number of days people hiked and camped, suggesting these are general preferences overall. © 2004 Wiley Periodicals, Inc.  相似文献   
3.
This article discusses creating a sustainably protective engineered and human management system in perpetuity for sites with long‐lived radiological and chemical hazards. This is essential at this time because the federal government is evaluating its property as assets and attempting to reduce its holdings, while seeking to assure that health and ecosystems are not put at risk. To assist those who have a stake in the remediation, management, and stewardship of these and analogous privately owned sites, this article discusses current end‐state planning by reviewing the federal government's accelerated efforts to reduce its footprint and how those efforts relate to sustainability. The article also provides a list of questions organized around six elements of risk management and primary, secondary, and tertiary disease and injury prevention. Throughout the article, the U.S. Department of Energy (DOE) is used as an example of an organization that seeks to reduce its footprint, manage its budget, and be a steward of the sites that it is responsible for. However, the approach and questions are appropriate for land controlled by the Department of Defense (DOD), the General Services Administration (GSA), and other public and private owners of sites with residual contamination. © 2005 Wiley Periodicals, Inc.  相似文献   
4.
A group of routine data entry operators (female) was included in the Polish MEPS (musculoskeletal--eyestrain--psychosocial--stress) study. Before the intervention, ergonomic assessment revealed improper working conditions such as inadequate lighting, uncomfortable chairs, and lack of forearm and wrist support while medical examination revealed that trapezius muscle load along with upper arm, head and back angles were higher than advisable. Subjects complained about neck and shoulder pain, visual problems, and psychosocial conditions. The ergonomic intervention included installation of new luminaires and Venetian blinds, new chairs, repair of ventilators, and optometric corrections. The results after the intervention showed mainly improvement in chair comfort, lighting conditions, visual strain, and sitting posture. However, financial limitations did not allow satisfactory completion of the intervention leading to a mixed interpretation of the results.  相似文献   
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6.
Cu, Cr, Mn, Ni and Zn contents were quantified for three wild-growing edible species of macrofungi (Boletus edulis, Macrolepiota procera and Cantharellus cibarius) and underlying soil samples collected at forest sites in Lubuskie voivodeship, Poland. The total concentration of the analysed elements was determined using an ASA iCE 3000 series atomic absorption spectrometer. The analysis found significant differences in bioaccumulation between species and differing distributions of trace elements in the caps and stalks of fruiting bodies. Bioaccumulation factors revealed that Zn and Cu are the most bioaccumulated elements, whereas Cr and Mn are excluded from bioaccumulation. Macrolepiota procera showed the highest bioaccumulation of Cu, and Zn is accumulated to the greatest extent by Boletus edulis. A few significant differences (p≤0.05) between the examined species were observed.  相似文献   
7.

In these studies, removal of Fe(III) ions by biosorption processes from aqueous solutions was carried out using paprika (Capsicum annuum L.) pomace generated during processing in the food industry. The biosorbent material was characterized using several analytical methods, including particle size distribution, XRD, SEM–EDS, electrokinetic zeta potential, surface area analysis (BET, BJH), thermogravimetry, morphology (SEM), spectrophotometry FT-IR. Several factors, such as biosorbent dosage, initial concentration, contact time and initial pH were analyzed to show an effect on the bioremoval process, efficiency and adsorption capacity. As a result, the maximum adsorption efficiency and capacity were determined to be 99.1% and 7.92 mg/g, respectively. Based on the kinetics analysis, the bioremoval process is better described by the Langmuir isotherm model and the pseudo-second order equation model. In conclusion, the achieved research results suggest that paprika biomass can be an effective material for efficiently removing iron(III) from wastewater and improving water quality. These studies on the recovery of iron metal from the environment fit in the latest trends in the concept of the global circular economy.

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8.
Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts. Definiendo el Impacto de las Especies No‐Nativas  相似文献   
9.

Among the wide range of compounds reaching the soil are the veterinary antimicrobials. Since no regulations regarding acceptable levels of drug concentrations in the environment exist, monitoring tests, particularly concerning soils, are carried out very rarely. This study presents a preliminary assessment of the contamination of agricultural soils in Northern Poland with seven antimicrobial veterinary medicines which has never been carried out before. Veterinary drugs were detected in 54% of the examined soil samples; the most commonly detected drugs were sulfonamides and trimethoprim. The highest indicated concentrations refer to enrofloxacin (57.0 μg kg?1) and trimethoprim (47.8 μg kg?1). The presence of these target drugs in the soil environment confirms the need for further monitoring studies. The analytical methods developed in this study are an excellent tool to achieve this goal and allow an estimation of the risk connected with the presence of veterinary antimicrobials in soils.

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10.

The retention of heavy metal (HM) was studied in root and rhizomes (BLG), stems (ST), and leaves (LF) of Phragmites australis (common reed) seedlings collected from different locations, differing in the scale of anthropogenic interference. The analysis includes the reference samples of sediments in uncontaminated lake Garczonki and contaminated roadside ditch in Cieplewo. The concentrations of Zn, Cu, Pb, Cd, Ni, and Cr were analyzed in plant tissues and sediments using the atomic absorption spectrometry and inductively coupled plasma mass spectrometry. The general assessment of sediments collected in the Garczonki lake showed a good environmental status; while in the roadside ditch in Cieplewo, the sediments were considerably polluted with HM. In the first stage of plant growth, all of the analyzed HMs are mainly inhibited by BLG system. The decreasing trend of elements was as follows: BLG > ST > LF. The organs followed different decreasing trends of HM concentration; the trend Zn > Cu > Ni > Cr > Pb > Cd was found in ST and LF for the Garczonki lake seedlings and for BLG and LF for the roadside ditch in Cieplewo seedlings. Zn showed the highest concentration, while Cd the lowest concentration in each of the examined organs. The bioaccumulation factor indicated the higher mobility of HM in seedlings in the Garczonki lake than in the roadside ditch in Cieplewo. The morphological studies suggest the good state and health of seedling from both sites; however, the reduction of root hair surface was observed for the roadside ditch seedlings. The anatomical studies present changes in the size of the nucleus and count of chloroplasts in LF. No reaction on HM contamination sediments in the seedlings from the roadside ditch in Cieplewo in the aerenchyma was noted. Potentially, both types of seedlings can be used to decontaminate environments rich in HM. However, the level of HM absorbed by seedlings (in the first stage of growth) should be considered due to the behavior in the target phytoremediation site.

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