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421.
Monitoring air quality in large urban agglomerations is the key to the prevention of air pollution-related problems in emerging mega-cities. The city of Wuhan is a highly industrialised city with >9 million inhabitants in Central China. Simultaneous PM10 sampling was performed during 1 year at one urban and one industrial site. Mean PM10 daily levels (156 microg m(-3) at the urban site and 197 microg m(-3) at the industrial hotspot) exceed the US-EPA or EU annual limit values by 3-4 times. A detailed study of daily speciation showed that the mean chemical composition of PM10 presents minimal differences between peak and low PM episodes. This implies that PM10 aerosols in the study area result from local emissions, and air quality management and abatement strategies in Wuhan should thus focus on local anthropogenic sources. The levels of some elements of environmental concern are relatively high (409-615 ngPb m(-3), 66-70 ngAs m(-3), 116-227 ngMn m(-3), 10-12 ngCd m(-3)) due to industrial, but also urban emissions. Principal component analysis identified a mineral source (probably cement and steel manufacture) and smelting as the main contributors to PM10 levels at the industrial site (34%), followed by a coal fired power plant (20%) and the anthropogenic regional background (16%). At the urban site the major PM10 source is a mixed coal combustion source (31%), followed by the anthropogenic regional background (28%) and traffic (16%).  相似文献   
422.

The present study sought to evaluate the effectiveness of vermicomposting for the valorization of distilled grape marc, one of the main solid by-products of the winery sector during a 56-day pilot-scale trial. The increase in the density and biomass of earthworms (Eisenia andrei) during the earlier stages of the process reflected the suitability of the distilled marc (Vitis vinifera L. cv. Mencía) as feedstock in order to sustain large earthworm populations on a pilot-scale level. Supporting this, from 14 days onwards the pH of Mencía distilled marc fell within weak-alkaline levels and the electrical conductivity was between 0.21 and 0.11 mS cm−2 providing optimum conditions for earthworm growth. A rapid decrease in microbial activity as well as in the content of total polyphenols, both indicative of stabilized materials was also recorded after 14 days of vermicomposting. Moreover, the content of macro- and micronutrients in the end product matched with those considered to have the quality criteria of a good vermicompost with respect to plant health and safe agricultural use. Altogether, it underlines the feasibility of vermicomposting as an environment-friendly approach for the biological stabilization of distilled grape marc fulfilling both environmental protection and fertilizer production.

  相似文献   
423.
Food sources for cultivated marine bivalves generally are not well identified, although they are essential for a better understanding of coastal ecosystems and for the sustainability of shellfish farming activities. In addition to phytoplankton, other organic matter sources (OMS), such as microphytobenthos and detritus (of terrestrial or marine origins), can contribute significantly to the growth of marine bivalves. The aim of this study was to identify the potential food sources and to estimate their contributions to the growth of the Pacific oyster (Crassostrea gigas) in two contrasting trophic environments of Normandy (France): the Baie des Veys (BDV) and the Lingreville area (LIN). Two sites were studied in the BDV area (BDV-S and BDV-N) and one in the LIN area. To estimate the contribution of each type of OMS, we used a combination of stable natural isotope composition (δ13C, δ15N) analysis of OMS and oyster tissue together with a modelling exercise. Field sampling was conducted every 2 months over 1 year. The sampled sources were suspended particulate organic matter from marine (PhyOM) and terrestrial (TOM) origins, microphytobenthos (MPB), detrital organic matter from the superficial sediment (SOM), and macroalgae (Ulva sp., ULV). A statistical mixing model coupled to a bioenergetic model was used to calculate the contributions of each different source at different seasons. Results showed that isotopic composition of the animal flesh varied with respect to the potential OMS over the year within each ecosystem. Significant differences were also observed among the three locations. For instance, the δ13C and δ15N values of the oysters ranged from −20.0 to −19.1‰ and from 6.9 to 10.8‰ at BDV-S, from −19.4 to −18.1‰ and from 6.4 to 10.0‰ at BDV-N, and from −21.8 to −19.4‰ and from 6.3 to 8.3‰ at LIN. The contributions of the different sources to oyster growth differed depending on the ecosystem and on the period of the year. Phytoplankton (PhyOM) predominated as the principal food source for oysters (particularly in the LIN location). MPB, TOM, and ULV detritus also possibly contributed to oysters’ diet during summer and autumn at the BDV-S and BDV-N sites. SOM was not considered an OMS because it was already a mix of the other four OMS, but rather a trophic reservoir that potentially mirrored the trophic functioning of marine ecosystems.  相似文献   
424.
This paper assesses land-use changes related to naturbanization processes on three biosphere reserves in Southern Europe. A comparative analysis has been done on the National Parks in Peneda-Gerês in North Portugal, Cévennes in South France and Sierra Nevada in South Spain, using Corine Land Cover data from 1990 until 2006. Results indicate that the process of land-use intensification is taking place in the frame of naturbanization dynamics that could jeopardize the role of Protected Areas. Focusing on the trends faced by National Parks and their surrounding territories, the analysis demonstrates, both in quantitative and spatial terms, the intensification processes of land-use changes and how it is important to know them for coping with increasing threats. The article concludes that in the current context of increasing stresses, a broader focus on nature protection, encompassing the wider countryside, is needed if the initiatives for biodiversity protection are to be effective.  相似文献   
425.
As many countries have privatized their water industries, there is increasing interest in comparing the efficiency of public and private water and sewerage companies (WaSCs). However, previous studies have not considered that privatization can be carried out following two main approaches: fully private WaSCs, which involve the sale of utilities to the private sector, and concessionary WaSCs, in which only the operation of the services is privatized. This paper investigates, for the first time, the impact of both privatization approaches on the efficiency of WaSCs. In doing so, data envelopment analysis (DEA) was applied. However, unlike traditional models, the metafrontier concept was used in this research as it cannot be assumed that fully private and concessionary WaSCs share the same production frontier. The empirical application focused on the Chilean water industry as it was privatized from 1998 to 2004 following the two approaches described. The results suggest that the performance of fully private WaSCs is better than that of concessionary WaSCs. The conclusions of this study will be of great interest to water authorities worldwide facing the challenge of water industry privatization.  相似文献   
426.
Access to extractive resources relies as much on technology and prices as it does on the power to designate ecological and economic meanings to water and other environmental goods. This paper examines the ways in which the mining industry uses scientific models to create meanings for water that in turn legitimizes their access to and control over it. To do so, this paper explores the relevance of combining biophysical analyses—in this case water metabolism—with an examination of those power relations and social constructions that coexist with and affect the flows of water. Based on empirical research, this paper analyzes the evolution of water management in the process of copper production at the Cobre las Cruces mine in southern Spain to identify present contradictions in the strategies adopted by the mining company to avoid water degradation. These contradictions are revealed by examining how water has been framed as a resource not susceptible to being used for purposes other than mining processes. We argue that those framing this environmental explanation—the regional government and the mining industry—are promoting net subtractions of water from an aquifer against current regulations.  相似文献   
427.
This study investigates the effects of the absence of trust in shaping relationships between officers and managers in Copacabana, Bolivia, particularly regarding the construction of a sanitary landfill for the city. The article builds on an abductive thematic analysis of observation and interview data. The data suggest that prior negative experiences and the absence of shared values are common arguments used by the residents to negotiate the conditions of public programme implementation. The study is inspired by the literature identifying the specific components of trust and the literature on lack of trust and distrust as it highlights the positive effects of scepticism. I conclude that a climate in which trust is absent leads residents to counter the risks involved in accepting the project. These findings can be used to revise and refine the well-established thesis that lack of trust leads to rejection.  相似文献   
428.
Cyclodextrins (CDs) can improve the apparent solubility and bioavailability of a variety of organic compounds through the formation of inclusion complexes; accordingly, they are suitable for application in innovative remediation technologies of contaminated soils. However, the different interactions in the tertiary system CD/contaminant/soil matrix can affect the bioavailability of the inclusion complex through the possible sorption of CD and CD complex in the soil matrix, as well as with the potential of the sorbed CD to form the complex, concurrent with the desorption processes. This work focuses in changes produced by three different CDs in soil sorption-desorption processes of chlorpyrifos (CPF), diazinon (DZN), and chlorothalonil (CTL), and their major degradation products, 3,5,6-trichloro-2-pyridinol (TCP), 2-isopropyl-6-methyl-4-pyrimidinol, and hydroxy-chlorothalonil (OH-CTL). Cyclodextrins used were β-cyclodextrin (β-CD), methyl-β-cyclodextrin (Mβ-CD), and 2-hydroxypropyl-β-cyclodextrin (HPβ-CD). The studied soils belong to the orders Andisol, Ultisol, and Mollisol with different organic matter contents, mineral composition, and pH. The apparent sorption constants were significantly lower for the three pesticides in the presence of all CDs. The highest displacement of sorption equilibria was produced by the influence of Mβ-CD, with the most pronounced effect for CPF, a pesticide strongly sorbed on soils. The same was obtained for TCP and OH-CTL, highlighting the need to assess the risk of generating higher levels of groundwater contamination with polar metabolites if degradation rates are not controlled. The highest desorption efficiency was obtained for the systems CPF-β-CD, DZN-Mβ-CD, and CTL-Mβ-CD. Since the degree of adsorption of the complex is relevant to obtain an increase in the bioavailability of the contaminant, a distribution coefficient for the complexed pesticide in all CD–soil–pesticide system was estimated by using the apparent sorption coefficients, the stability constant for each CD–pesticide complex, and the distribution coefficients of free pesticide.  相似文献   
429.
In general, approved Total Allowable Catches (TACs) are higher than proposed TACs by the scientific assessment and reported landings approved are higher than approved TAC. We build a simple enforcement agency’s behavior model that generates—as a rational behavior—those two facts. The model has two ingredients. First, there exists illegal fishing generated by an imperfect enforcement technology; second, the enforcement agency cannot commit on announced penalties. We show that lack of commitment increases the potential benefits for national enforcement agency of deviating from proposal (scientific optimal) quotas. Although the enforcement agency wants to announce a low quota target to induce a low level of illegal harvest, it will find optimal to revise the quota announced in order to reduce penalties and improve fishermen welfare. Therefore, agencies find it optimal to approve higher quotas than that proposed by the scientific advice. Our main result is to show that when full compliance is not possible, and national agencies cannot commit, the introduction of Individual Transferable Quotas increases the potential benefits for agencies of deviating from the optimal proposed TAC by the scientific advised.  相似文献   
430.
Aquaculture farmers commonly add tetracycline to fish feed or to their ponds to prevent or treat bacterial infections in their crops. To assess the short-term effect of tetracycline (TET) and of one of its reversible epimers, 4-epitetracycline (ETC), on the function and structure of a sediment microbial community from a tropical tilapia farm, we contrasted community-level physiological profiles (CLPP) and phospholipid fatty acid profiles (PLFA) obtained from microcosms exposed for 12 days to 5, 10, 50, or 75 mg kg?1of these antibiotics. Notwithstanding that the concentration of the antibiotics during the experiment decreased between 13–100% (TET) or 16–61% (ETC), both compounds provoked opposing metabolic responses that did not revert. TET displayed a tendency to inhibit respiration at concentrations < 50 mg kg?1, whereas ETC showed the opposite effect. As revealed by the finding of the fatty acids 11:0 iso 3OH, 16:1w6c, and 18:1w6c, the sediment analyzed was predominantly colonized by Gram-negative bacteria. A marked decrease in fatty acid diversity accompanied the aforementioned metabolic responses, with TET concentrations > 50 mg kg?1leading to an enrichment of yeast and fungal biomarkers and both antibiotics at concentrations < 10 mg kg?1selecting for microorganisms with 11:0 iso 3OH. In agreement with CLPP data, differences between the PLFA profiles of control and treated microcosms were more pronounced for TET than for ETC. We conclude that high, yet field-relevant, concentrations of TET and ETC have the potential to modify the composition, and to a lesser extent, the functioning of a sediment microbial community. This study highlights the importance of considering antibiotic degradation products in ecotoxicological research.  相似文献   
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