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791.
Maria Teresa García Gema Duque Ignacio Gracia Antonio de Lucas Juan F. Rodríguez 《Journal of Material Cycles and Waste Management》2009,11(1):2-5
The amount of extruded polystyrene (XPS) waste has increased in recent years due to the increase of its use in the thermal
insulation of buildings, transport vehicles, and refrigerators, among others. Dissolution with suitable solvents to achieve
a volume reduction of more than 100 times without degradation of polymer chains is one of the cheapest and most efficient
methods of recycling XPS. Several environmentally friendly solvents have been tested as dissolution agents for XPS volume
reduction; the action of these solvents does not produce any degradation of polymer chains. The solubility of the polymer
in such solvents at different temperatures was investigated. The solvent can be easily recycled by distillation, obtaining
a high-quality recycled polymer.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
792.
Sanchez-Hernandez JC Wheelock CE 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):264-272
A laboratory-based study was conducted to determine the basal carboxylesterase (CbE) activity in different tissues of the earthworm Lumbricus terrestris, and its sensitivity to the organophosphate (OP) pesticide chlorpyrifos-oxon (CPx). Carboxylesterase activity was found in the pharynx, crop, gizzard, anterior intestine, wall muscle and reproductive tissues of L. terrestris, and multiple tissue-specific isozymes were observed by native gel electrophoresis. Esterase activity and sensitivity to CPx inhibition varied on a tissue- and substrate-specific basis, suggesting isoforms-specific selectivity to OP-mediated inhibition. Three practical issues are recommended for the use of earthworm CbE activity as a biomarker of pesticide exposure: (i) CbE should be measured using several routine substrates, (ii) it should be determined in selected tissues instead of whole organism homogenate, and (iii) earthworm CbE activity should be used in conjuncture with other common biomarkers (e.g., ChE) within a multibiomarker approach to assess field exposure of OPs, and potentially other agrochemicals. 相似文献
793.
Enric Saiz Juancho Movilla Carlos Barata 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1219-1226
Short-term (24 h) exposure experiments have been conducted to determine the effects of two environmental relevant polycyclic aromatic hydrocarbons (PAHs), naphthalene (NAPH) and dimethylnaphthalene (C2-NAPH), on the naupliar and adult stages of the marine cyclopoid copepod Oithona davisae. To resemble more realistic conditions, those exposure experiments were conducted under the presence of food. The naupliar stages evidenced lower tolerance to PAH exposure regarding narcotic and lethal effects than adults. Copepod feeding activity showed to be very sensitive to the presence of the studied PAHs, detrimental effects occurring at toxic concentrations ca. 2-3 fold lower than for narcotic effects. In addition we report PAH-mediated changes in cell size and growth rate of the prey item, the heterotrophic dinoflagellate Oxyrrhis marina, that could indirectly affect copepod feeding and help explain hormesis-like responses in our feeding experiments. 相似文献
794.
João Canário Laurier Poissant Carlos Vale David Lean 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1294-1300
An open-bottom and a closed-bottom mesocosm were developed to investigate the release of mercury from sediments to the water column in a frozen freshwater lake. The mesoscosms were deployed in a hole in the ice and particulate mercury (HgP) and total dissolved mercury (TDHg) were measured in sediments and in water column vertical profiles. In addition, dissolved gaseous mercury (DGM) in water and mercury water/airflux were quantified. Concentrations of TDHg, DGM, and mercury flux were all higher in the open-bottom mesocosm than in the closed-bottom mesocosm. In this paper we focus on the molecular diffusion of mercury from the sediment in comparison with the TDHg accumulation in the water column. We conclude that the molecular diffusion and sediment resuspension play a minor role in mercury release from sediments suggesting that solute release during ebullition is an important transport process for mercury in the lake. 相似文献
795.
796.
Carlos Sanchez Tze-San Lee Stacy Young Dahna Batts Jefferson Benjamin Josephine Malilay 《Disasters》2009,33(4):705-720
This study examines health effects resulting from landslides in Chuuk during Tropical Storm Chata'an in July 2002, and suggests strategies to prevent future mortality. In August 2002, we conducted a cross-sectional survey to identify risk factors for mortality during landslides, which included 52 survivors and 40 surrogates for 43 decedents to identify risk factors for death. Findings suggest that 1) females had a higher mortality rate from this event than males, and 2) children aged 5–14 years had a 10-fold increase in mortality when compared with annual mortality rates from all causes. Awareness of landslides occurring elsewhere and knowledge of natural warning signs were significantly associated with lower risks of death; being outside during landslides was not associated with reduced mortality. In Chuuk, improving communication systems during tropical storms and increasing knowledge of natural warnings can reduce the risk for mortality during landslides. 相似文献
797.
798.
根据数理统计的原理,将环境质量标准,平均值,标准偏差以及样本容量综合进行考虑,提出了污染分界线的计算公式,并以表格形式给出了不同显著性水平下,不同的相对标准偏差和样本容量所对应的污染分界线,对污染分界线与样本容量及相对标准的偏差的关系进行了讨论,指出提高监测精度和适当增加监测数据个数,可以使污染分界线接近评价标准。 相似文献
799.
Sellek R Jimenez O Aizpurua C Fernandez-Frutos B De Leon P Camacho M Fernandez-Moreira D Ybarra C Carlos Cabria J 《Journal of environmental monitoring : JEM》2008,10(3):362-369
The aim of this study was to develop a specific and highly sensitive method able to detect very low concentrations of Francisella tularensis in soil samples by real-time PCR (qPCR) with SYBR Green I. tul4 gene, which encodes the 17-kDa protein (TUL4) in F. tularensis strains, was amplified using a LightCycler (LC) device. We achieved a detection limit of 0.69 fg of genomic DNA from F. tularensis subp. holarctica live vaccine strain (LVS), corresponding to a value less than 3.4 genome equivalents per reaction. The qPCR was shown to be specific, highly sensitive and reproducible. In addition, we evaluated 2 new methods for recovering bacteria from soil based on 1-step filtration using glass fiber filters and PVDF filters. These filtration methods enabled us to recover F. tularensis efficiently from soil samples. As few as 50 CFU per 0.5 g of soil were detected by qPCR. Capture enzyme-linked immunosorbent assay (cELISA) allowed us to detect and quantify the amount of bacteria recovered from soil by an immunological method. Although qPCR was more sensitive than cELISA, we did not observe substantial differences in the amount of bacteria quantified by both methods. 相似文献
800.
从政府与农户的动态博弈分析退耕还林工程的可持续性 总被引:10,自引:0,他引:10
退耕还林工程的实施取得了一定的成绩,但是也存在一些问题,制约了工程的可持续性。其中一个重要的原因就是补偿问题。通过经济学中的博弈理论构建退耕还林动态模型,从补偿的角度分析了退耕还林工程中存在的问题,并提出工程可持续性建议,即:①对生态林和经济林实行差别补偿;②对不同地区实行差别补偿标准;③延长补偿期限,实行分年度对农户进行不同数量的补偿;④对工程区进行产业结构调整,加强农户技能培训。 相似文献