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671.
Andersen JK Boldrin A Christensen TH Scheutz C 《Waste management (New York, N.Y.)》2011,31(9-10):1934-1942
A comprehensive experimental setup with six single-family home composting units was monitored during 1 year. The composting units were fed with 2.6-3.5 kg organic household waste (OHW) per unit per week. All relevant consumptions and emissions of environmental relevance were addressed and a full life-cycle inventory (LCI) was established for the six home composting units. No water, electricity or fuel was used during composting, so the major environmental burdens were gaseous emissions to air and emissions via leachate. The loss of carbon (C) during composting was 63-77% in the six composting units. The carbon dioxide (CO(2)) and methane (CH(4)) emissions made up 51-95% and 0.3-3.9% respectively of the lost C. The total loss of nitrogen (N) during composting was 51-68% and the nitrous oxide (N(2)O) made up 2.8-6.3% of this loss. The NH(3) losses were very uncertain but small. The amount of leachate was 130 L Mg(-1) wet waste (ww) and the composition was similar to other leachate compositions from home composting (and centralised composting) reported in literature. The loss of heavy metals via leachate was negligible and the loss of C and N via leachate was very low (0.3-0.6% of the total loss of C and 1.3-3.0% of the total emitted N). Also the compost composition was within the typical ranges reported previously for home composting. The level of heavy metals in the compost produced was below all threshold values and the compost was thus suitable for use in private gardens. 相似文献
672.
The influence of socioeconomic, environmental, and demographic factors on municipality-scale land-cover change in Mexico 总被引:3,自引:0,他引:3
Martha Bonilla-Moheno T. Mitchell Aide Matthew L. Clark 《Regional Environmental Change》2012,12(3):543-557
Land-cover change is the result of complex multi-scale interactions between socioeconomic, demographic, and environmental factors. Demographic change, in particular, is thought to be a major driver of forest change. Most studies have evaluated these interactions at the regional or the national level, but few studies have evaluated these dynamics across multiple spatial scales within a country. In this study, we evaluated the effect of demographic, environmental, and socioeconomic variables on land-cover change between 2001 and 2010 for all Mexican municipalities (n?=?2,443) as well as by biome (n?=?4). We used a land-cover classification based on 250-m MODIS data to examine the change in cover classes (i.e., woody, mixed woody, and agriculture/herbaceous vegetation). We evaluated the trends of land-cover change and identified the major factors correlated with woody vegetation change in Mexico. At the national scale, the variation in woody vegetation was best explained by environmental variables, particularly precipitation; municipalities where woody cover increased tended to be in areas with low average annual precipitation (i.e., desert and dry forest biomes). Demographic variables did not contribute much to the model at the national scale. Elevation, temperature, and population density explained the change in woody cover when municipalities were grouped by biome (i.e., moist forest, dry forest, coniferous forest, and deserts). Land-cover change at the biome level showed two main trends: (1) the tropical moist biome lost woody vegetation to agriculture and herbaceous vegetation, and (2) the desert biome increased in woody vegetation within more open-canopy shrublands. 相似文献
673.
Brouwers MM Besselink H Bretveld RW Anzion R Scheepers PT Brouwer A Roeleveld N 《Environment international》2011,37(3):557-564
Measurements of estrogenic and androgenic activities in total plasma with Chemically Activated LUciferase gene eXpression (CALUX?) bioassays could provide biologically relevant measures for exposure to endocrine disruptors in epidemiologic studies. The objective of this study was to explore the effects of a variety of sources of potential endocrine disruptors on estrogenic and androgenic activities in total plasma measured by CALUX?. Plasma samples and interview data on sources of potential endocrine disruptors were collected from 108 men with different exposures profiles. CALUX? measurements (BioDetection Services) involved human U2-OS cell lines controlled by the estrogen receptor alpha and the androgen receptor. Mean differences (beta) in 17β-estradiol equivalents (EEQs) and dihydrotestosterone equivalents (AEQs) between exposure groups were estimated using general linear models. Mean plasma AEQs and EEQs were 9.1×10(-1)ng/ml and 12.0pg/ml, respectively. Elevated AEQs were found in smokers (beta 1.9 (95%CI 0.1-3.6)×10(-1)ng/ml) and heavy drinkers (1.4 (0.2-3.1)×10(-1)ng/ml), and in men occupationally exposed to disinfectants (1.6 (0.3-3.5)×10(-1)ng/ml) or welding/soldering fumes (1.4 (-0.2-2.9)×10(-1)ng/ml). Occupational exposure to pesticides, disinfectants, and exhaust fumes seemed to be associated with increased plasma EEQs: 1.5 (-0.2-3.2)pg/ml, 2.1 (0.2-3.9)pg/ml, and 2.9 (0.6-5.2)pg/ml, respectively. Moderate to high plasma dioxin levels, measured in a subgroup by the dioxin-responsive CALUX?, were accompanied by a 20% increase in AEQs. This is the first study in which CALUX? was used to assess hormone activities in total plasma. Although the results are not yet readily interpretable, they indicate that these measurements can be valuable for epidemiologic studies on endocrine disruptors and give direction for further research. 相似文献
674.
Alexandrova M Rozhko T Vydryakova G Kudryasheva N 《Journal of environmental radioactivity》2011,102(4):407-411
The effect of americium-241 (241Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of 241Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 °C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the 241Am is discussed. The effect of 241Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in 241Am solutions was demonstrated; and the similarity of 241Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. 相似文献
675.
Although marine and terrestrial emissions simultaneously affect the formation of atmospheric fine particles in coastal areas, knowledge on the optical properties and sources of water-soluble matter in these areas is still scarce. In this work, taking Qingdao, China as a typical coastal location, the chemical composition of PM2.5 during winter 2019 was analyzed.Excitation-emission matrix fluorescence spectroscopy was combined with parallel factor analysis model to explain the component... 相似文献
676.
R. Clément M. Descloitres T. Günther L. Oxarango C. Morra J.-P. Laurent J.-P. Gourc 《Waste management (New York, N.Y.)》2010,30(3):452-464
Leachate recirculation is a key process in the scope of operating municipal waste landfills as bioreactors, which aims to increase the moisture content to optimize the biodegradation in landfills. Given that liquid flows exhibit a complex behaviour in very heterogeneous porous media, in situ monitoring methods are required. Surface time-lapse electrical resistivity tomography (ERT) is usually proposed. Using numerical modelling with typical 2D and 3D injection plume patterns and 2D and 3D inversion codes, we show that wrong changes of resistivity can be calculated at depth if standard parameters are used for time-lapse ERT inversion. Major artefacts typically exhibit significant increases of resistivity (more than +30%) which can be misinterpreted as gas migration within the waste. In order to eliminate these artefacts, we tested an advanced time-lapse ERT procedure that includes (i) two advanced inversion tools and (ii) two alternative array geometries. The first advanced tool uses invariant regions in the model. The second advanced tool uses an inversion with a “minimum length” constraint. The alternative arrays focus on (i) a pole–dipole array (2D case), and (ii) a star array (3D case). The results show that these two advanced inversion tools and the two alternative arrays remove almost completely the artefacts within +/?5% both for 2D and 3D situations. As a field application, time-lapse ERT is applied using the star array during a 3D leachate injection in a non-hazardous municipal waste landfill. To evaluate the robustness of the two advanced tools, a synthetic model including both true decrease and increase of resistivity is built. The advanced time-lapse ERT procedure eliminates unwanted artefacts, while keeping a satisfactory image of true resistivity variations. This study demonstrates that significant and robust improvements can be obtained for time-lapse ERT monitoring of leachate recirculation in waste landfills. 相似文献
677.
The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 °C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 ± 36 ml CH4/d before the addition of glycerol and 2353 ± 94 ml CH4/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (μmax) and the saturation constant (KS) of glycerol were 0.149 ± 0.015 h?1 and 0.276 ± 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process. 相似文献
678.
MADELEINE C. BOTTRILL MORENA MILLS ROBERT L. PRESSEY EDWARD T. GAME CRAIG GROVES 《Conservation biology》2012,26(5):851-861
Abstract: The outcomes of systematic conservation planning (process of assessing, implementing, and managing conservation areas) are rarely reported or measured formally. A lack of consistent or rigorous evaluation in conservation planning has fueled debate about the extent to which conservation assessment (identification, design, and prioritization of potential conservation areas) ultimately influences actions on the ground. We interviewed staff members of a nongovernmental organization, who were involved in 5 ecoregional assessments across North and South America and the Asia‐Pacific region. We conducted 17 semistructured interviews with open and closed questions about the perceived purpose, outputs, and outcomes of the ecoregional assessments in which respondents were involved. Using qualitative data collected from those interviews, we investigated the types and frequency of benefits perceived to have emerged from the ecoregional assessments and explored factors that might facilitate or constrain the flow of benefits. Some benefits reflected the intended purpose of ecoregional assessments. Other benefits included improvements in social interactions, attitudes, and institutional knowledge. Our results suggest the latter types of benefits enable ultimate benefits of assessments, such as guiding investments by institutional partners. Our results also showed a clear divergence between the respondents’ expectations and perceived outcomes of implementation of conservation actions arising from ecoregional assessments. Our findings suggest the need for both a broader perspective on the contribution of assessments to planning goals and further evaluation of conservation assessments. 相似文献
679.
680.
In the midst of rapidly proliferating engagement efforts around climate adaptation, attention to the design and evaluation of decision support processes and products is warranted. We report on the development and evaluation of a process framework called the Vulnerability, Consequences, and Adaptation Planning Scenarios (VCAPS) process. VCAPS is a systematic approach to integrate local knowledge with scientific understanding by providing opportunities for facilitated, deliberative learning-based activities with local decision makers about climate change vulnerability and adaptation. We introduce the conceptual basis of the process in analytic-deliberation, hazard management, and vulnerability. Our evaluations from eight coastal communities where the approach was applied point to four assets of VCAPS: it promotes synthesis of local and scientific knowledge; it stimulates systems thinking and learning; it facilitates governance by producing action plans with transparent justifications; and it accommodates participant time constraints and preferences. 相似文献