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101.
It is a current practice that refrigerators and freezers in many countries are shredded after the end of useful lives. The shredder residue is deposited in landfills. During the shredding process a significant fraction of blowing agent (BA) in the insulation foam may be released into the atmosphere. The objective of this study is to determine the fraction of BA released from foam during shredding, by comparing the BA content in insulation foam of refrigerator units before shredding with the BA content of shredded foam. All foam samples analyzed were manufactured with trichlorofluoromethane [CFC-11 (CCl3F)] as BA. The average content of BA in the insulation foam from eight U.S. refrigerator units manufactured before 1993 was found to be 14.9% +/- 3.3% w/w. Several refrigerator units also identified as being manufactured before 1993 were stockpiled and shredded at three shredder facilities, of which one was operated in both wet and dry modes. The selected shredder facilities represent typical American facilities for shredding automobiles, refrigerators, freezers, and other iron containing waste products. Shredded material was collected and separated on location into four particle size categories: more than 32 mm, 16-32 mm, 8-16 mm, and 0-8 mm. Adjusting for sample purity, it was found that the majority (>81%) of the foam mass was shredded into particles larger than 16 mm. The smallest size fraction of foam (0-8 mm) was found to contain significantly less BA than the larger size categories, showing that up to 68% +/- 4% of the BA is released from these fine particles during the shredding process. Because only a minor fraction of the foam is shredded into particles smaller than 8 mm, this has a minor impact on the end result when calculating the total BA release from the shredding process. Comparing BA content in shredded samples from the three shredder facilities with the measured average BA content of the eight refrigerator units, it was found that on average 24.2% +/- 7.5% of the initial BA content is released during the shredding process.  相似文献   
102.
Measurements of nitrogen dioxide, nitrous and nitric acids as well as ozone were made using newly developed instrumentation onboard the research vessel Aegeon in the Aegean Sea between 25th–29th July 2000. Typical nitrogen dioxide concentrations observed aboard the boat were 4–6 ppb (v/v) with a broad maximum of 20–30 ppb (v/v). Ozone concentrations typically ranged between 40 and 80 ppb (v/v). Mixing ratios of both nitric and nitrous acids in the ambient air of the Aegean Sea were mainly below 50 ppt (v/v). The data also showed a number of short pollution episodes with rapid changes in the concentration of reactive nitrogen compounds [nitrogen dioxide maximum up to 164 ppb (v/v), nitric acid maximum up to 12 ppb (v/v), nitrous acid maximum up to 2.7 ppb (v/v)] and ozone [maximum up to 88 ppb (v/v)]. These episodes were correlated with pollution plumes originating from boats upwind, at short distance, from the R/V Aegeon. The measurements revealed the importance of nitrous and nitric acids for the transport of nitrogen to marine biota in busy ship lanes.  相似文献   
103.
104.
ABSTRACT

The core themes and research questions of this volume, centred on the nature of environmental policy change in the European Union (EU), are laid out. An original heuristic framework to capture different dimensions, mechanisms and processes of policy change is presented. In order to contextualise the current situation, where EU policy scope has reached maturity and faces an uncertain future trajectory, EU environmental politics is divided into particular eras, looking closely at the nature of change in each period. This volume interrogates the extent to which change has occurred, the conditions or context within which it did/did not take place and the implications arising from stasis or change. The contributions to the volume are introduced and placed into the context of the broader trajectory of EU environmental policy.  相似文献   
105.
A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.  相似文献   
106.
The biochemical methane potential (BMP) is an essential parameter when using first order decay (FOD) landfill gas (LFG) generation models to estimate methane (CH4) generation from landfills. Different categories of waste (mixed, shredder and sludge waste) with a low-organic content and temporarily stored combustible waste were sampled from four Danish landfills. The waste was characterized in terms of physical characteristics (TS, VS, TC and TOC) and the BMP was analyzed in batch tests. The experiment was set up in triplicate, including blank and control tests. Waste samples were incubated at 55 °C for more than 60 days, with continuous monitoring of the cumulative CH4 generation. Results showed that samples of mixed waste and shredder waste had similar BMP results, which was in the range of 5.4–9.1 kg CH4/ton waste (wet weight) on average. As a calculated consequence, their degradable organic carbon content (DOCC) was in the range of 0.44–0.70% of total weight (wet waste). Numeric values of both parameters were much lower than values of traditional municipal solid waste (MSW), as well as default numeric values in current FOD models. The sludge waste and temporarily stored combustible waste showed BMP values of 51.8–69.6 and 106.6–117.3 kg CH4/ton waste on average, respectively, and DOCC values of 3.84–5.12% and 7.96–8.74% of total weight. The same category of waste from different Danish landfills did not show significant variation. This research studied the BMP of Danish low-organic waste for the first time, which is important and valuable for using current FOD LFG generation models to estimate realistic CH4 emissions from modern landfills receiving low-organic waste.  相似文献   
107.
Most studies of animal personality attribute personality to genetic traits. But a recent study by Magnhagen and Staffan (Behav Ecol Sociobiol 57:295–303, 2005) on young perch in small groups showed that boldness, a central personality trait, is also shaped by social interactions and by previous experience. The authors measured boldness by recording the duration that an individual spent near a predator and the speed with which it fed there. They found that duration near the predator increased over time and was higher the higher the average boldness of other group members. In addition, the feeding rate of shy individuals was reduced if other members of the same group were bold. The authors supposed that these behavioral dynamics were caused by genetic differences, social interactions, and habituation to the predator. However, they did not quantify exactly how this could happen. In the present study, we therefore use an agent-based model to investigate whether these three factors may explain the empirical findings. We choose an agent-based model because this type of model is especially suited to study the relation between behavior at an individual level and behavioral dynamics at a group level. In our model, individuals were either hiding in vegetation or feeding near a predator, whereby their behavior was affected by habituation and by two social mechanisms: social facilitation to approach the predator and competition over food. We show that even if we start the model with identical individuals, these three mechanisms were sufficient to reproduce the behavioral dynamics of the empirical study, including the consistent differences among individuals. Moreover, if we start the model with individuals that already differ in boldness, the behavioral dynamics produced remained the same. Our results indicate the importance of previous experience and social interactions when studying animal personality empirically.  相似文献   
108.
Orthophosphate monoesters often constitute a significant fraction of total phosphorus in lake sediments. The knowledge on the specific composition and recalcitrance of these compounds is however limited. The main aim was therefore to identify and quantify specific orthophosphate monoesters in sediment from 15 Danish lakes by solution (31)P NMR spectroscopy. The four most quantitatively important orthophosphate monoesters were myo-inositol hexakisphosphate (myo-IP(6)), scyllo-inositol hexakisphosphate (scyllo-IP(6)) α-glycerophosphate (α-GP) and β-glycerophosphate (β-GP). The compounds were identified in 9, 4, 8 and in all 15 lakes, respectively. In total these four components made up 46-100% of the orthophosphate monoester pool. The glycerophosphates (GPs) are most likely degradation products of phospholipids, created as an artifact by the alkaline extraction procedure used for (31)P NMR spectroscopy, while the inositol hexakisphosphates (IPs) are naturally occurring compounds. There was a significant positive correlation between myo-IP(6) and total aluminium in the sediment and a negative correlation between myo-IP(6) and lake water pH, suggesting that myo-IP(6) is stabilized in the sediment by adsorption at slightly acidic or neutral conditions. In three lakes, the depth distribution of the orthophosphate monoesters was investigated. The content of scyllo-IP(6) and myo-IP(6) was constant with sediment depth in two of the lakes while the content of myo-IP(6) decreased with depth in one of the lakes. In all cases the IPs seem to be preserved with sediment depth to a higher extent than the orthophosphate diesters and especially the GPs suggesting that IPs can be a sink for phosphorus in the lake ecosystem or at least delay P-recycling for years.  相似文献   
109.
Germline pathogenic variants in isocitrate dehydrogenase 1 (IDH1) can lead to a rare neurodevelopmental disorder called metaphyseal chondromatosis with D-2-hydroxyglutaric aciduria, including severe skeletal and cerebral anomalies. To the best of our knowledge, no prenatal case of an IDH1 pathogenic variant has been reported in literature. Somatic sequence variants in IDH1/2 genes are described in distinct cancers, premalignant diseases and rare inherited metabolic disorders. Amniocentesis and further genetic testing including trio exome sequencing were performed due to suspicious findings on a second trimester routine prenatal ultrasound examination. The fetus was found to have growth restriction, cerebral abnormalities (ex vacuo hydrocephalus, cerebellar and vermian hypoplasia, corpus callosum dysgenesis), brachycephaly, narrow chest, persistent left superior vena cava, liver calcifications, hyperechogenic bowel, short tubular bones and joint contractures. A de novo heterozygous variant in the IDH1 gene was detected via trio exome sequencing. The prenatal diagnosis of a de novo pathogenic variant in IDH1 in a fetus with the described phenotype, obtained through trio exome sequencing, helped parents and providers with an informed decision making about pregnancy management.  相似文献   
110.
Environmental Science and Pollution Research - The organochlorine pollution by chlordecone, an insecticide spread in the past in banana plantations, is now recognized as a major ecological,...  相似文献   
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