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271.
The results of a study of photocatalytic degradation of phenol using aqueous oxygenated TiO2 (anatase) suspensions in a batch Pyrex photoreactor are reported. The influence on the photodegradation rate of various parameters as pH, phenol and TiO2 content, oxygen partial pressure, anions present in the dispersions was investigated. A complete oxidation of phenol was observed. Intermediate compounds, catechol and quinone, were detected. It was observed that the photodegradation also proceeded with sunlight radiation. A mechanistic and kinetic model, which accounts for the results obtained, is given. Likely reasons for inactivity of the rutile modification for this reaction are also given. 相似文献
272.
The hypotheses on the de novo syntheses of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo‐p‐dioxins (PCDDs), based on known literature, are presented. Polychlorinated benzenes and polychlorinated phenols are probably key intermediates. In the present article, hypotheses that may account for the presence of polychlorinated dibenzofurans (PCDFs) and dibenzo‐p‐dioxins (PCDDs) in the effluents from municipal and industrial incinerators are put forward. These hypotheses are based on the previously surveyed literature (Ref. 203–206) and experimental results on laboratory scale and thermodynamic calculations are considered. The interconnections of various reaction steps are speculative and no technological information was added to account for conditions in real incinerators. Conclusion of the discussions on the related subject matter, presented in the Parts I‐IV (Ref. 203–206), are also described in this paper. 相似文献
273.
An accurate, simple and cheap extraction and cleanup procedure for capillary GC analysis of organo‐chlorine insecticides (OCs) in vegetables (cabbage and carrots) at the ng/g level, and for soil at the μg/g level is presented. The cleanup is carried out on solid‐phase extraction (SPE) cartridges, filled with 500 mg silica, 1 g of deactivated Florisil (10% w/w water), and 100 mg of anhydrous sodium sulphate. Recoveries >90% are obtained. The cleanup of OCs in fatty samples on an HPLC LiChrosorb Si 100 column is evaluated for subsequent capillary GC analysis. Fractionation of OCs and Aroclor 1254 and 1260 on an HPLC Nucleosil 100 column appears to be satisfactory. 相似文献
274.
A receptor modeling approach has been applied to identify and apportion sources of airborne particulate matter in Thessaloniki, Greece. The absolute principal component analysis source apportionment technique used, provided quantitative information regarding both source particle characteristics and impacts. The analysis identified four major sources of heavy metals within total suspended particles (TSP) in the centre of the city: oil burning, pyrometallurgical non‐ferrous metal processes, motor vehicles and soil resuspension. Their contributions to TSP estimated by regression on absolute principal component scores (APCS) were 12%, 8%, 5% and 4%, respectively. A similar analysis conducted for a sampling site close to the industrial area identified five major sources: oil burning, industrial Cr source, soil resuspension, pyrometallurgical non‐ferrous metal processes and motor vehicles with contributions 20%, 15%, 9%, 8% and 4%, respectively. 相似文献
275.
The influence of the type of clouds that produce precipitation in the rainwater composition was analyzed. Logroño, a remote station in the North of Spain was chosen for the analyses. Results prove that the rainwater composition from Cumulonimbus is different to the composition of the rainwater from the other clouds. In addition, the source of NO3 ? and SO4 2? is studied in the different types of clouds. It is shown that the source is the soil except Stratocumulus formed from Cumulus in which the source is the gas‐particle conversion. 相似文献
276.
Donghan Yu 《毒物与环境化学》2013,95(3-4):281-295
This paper presents an uncertainty and sensitivity analysis of a pharmacokinetic modeling of inorganic arsenic deposition in rodents for a short‐term exposure. Efforts to develop the pharmacokinetic model are directed towards predicting the kinetic behavior of inorganic arsenic in the body, including tissue and blood concentrations, and especially, the urinary excretion of arsenic and its methylated metabolites. However, the use of the model raises an important question when fixed values of model parameters are used: how is the uncertainty in the model prediction based on the collective uncertainties in the model inputs? This study focuses on an “epistemic”; uncertainty in order to handle this problem. In this case, the uncertainty refers to an input that has a single value which cannot be known with precision due to a lack of knowledge about items or its measurement. The combination of the pharmacokinetic model and the uncertainty analysis would help understand the uncertainties in risk assessment associated with inorganic arsenic. 相似文献
277.
Brian G. Field Brian G. Field J. N.R. Jeffers R. J. Livingston Jonathan Cowie 《国际发展与全球生态学杂志》2013,20(1):85-90
The aim of sustainable development is to balance social, economic, and environmental needs. In order to justify the decisions they make, stakeholders must quantify the different impacts found in the operations and developments of companies and/or projects throughout their life cycle. However, as some areas are subjective in nature, the quantification process of the different impacts and the assessment of sustainable development performance become arduous tasks of development, validation, and application of scientific and empirical methods with the intrinsic objective of finding an agreement among the involved parties (i.e., stakeholders). Several environmental and sustainability assessment tools, instruments, processes, and methodologies have been developed; rating systems stand out and have gained attention and credibility, as demonstrated by the vast number of certified projects around the world and the widely-known usefulness and advantages of their application. The Wa-Pa-Su project sustainability rating system presents an integrated approach to sustainability assessment by integrating three distinctive areas of knowledge: (1) sustainable development theory and fundamentals supports the ultimate goal of the rating system, which is to contribute to sustainability, with the aim of finding a path to balance social, economic, and environmental needs; (2) continual performance improvement becomes essential due to the duration of the projects, as it is critical to allow organizations or projects to improve performance over time; and (3) multi-criteria decision analysis assists with the assessment process through stakeholder engagement and participation, and the design and implementation of a criteria weighting system. 相似文献
278.
SUMMARY This study explores differences among organic farmers who live in islands and have isolated small-size operations. The relationships between farmers' characteristics and attitudes and farm management were interpreted by studying how they manage their land, their attitudes towards the environment and alternative farming systems, and their involvement in organic farming. The research was carried out using questionnaires addressed to organic farmers on the island of Thassos. Nonlinear canonical correlation was applied for data analysis. This information could contribute to adjustment of policy decisions for on-farm diversification. Agricultural policy makers should approach organic farmers in northern Thassos (productive irrigated olive orchards with gentle slopes) by enacting standards to reduce the cost of alternative plant protection methods and promoting their products in order to maintain and expand organic farming. They should also approach organic farmers in southern Thassos (less productive, dry cultivated olive orchards with steep slopes, overgrazed and often abandoned) by providing them with the necessary information and appropriate agricultural know-how to effectively manage their farms. Organic farmers with stable off-farm income are more aware of environmental values and consider that they risk less than others in order to gain the benefits of alternative farming systems. However, they should attend training programmes to achieve economic success to allow them to continue farming organically. 相似文献
279.
In recent years, it has been important to objectively evaluate the degree of regional ecological security with regard to resource depletion and to analyse influential factors to assess sustainable development. This paper tries to assess ecological security in Chongqing while investigating the main influencing factors. Calculations of the consumption footprint, production footprint and ecological capacity for Chongqing from 1996 to 2007 based on an ecological footprint approach were carried out. An ecological security index was also calculated from these results and factors influencing security were analysed using factor analysis. Both the consumption and production footprints present an upward trend, contrary to the gradually decreasing trend of ecological capacity. In addition, the ecological security index shows that Chongqing has deteriorated from a level of less risk to that of risk. Factor analysis suggests that the deterioration of ecological security could primarily be ascribed to socio-economic factors and industrialisation. With socio-economic development and industrialisation, appropriate measures must be taken to improve the ecosystem in Chongqing so as to achieve sustainable development. The limitations of the methodology are also discussed and areas that require further research are presented. 相似文献
280.
Luca Salvati 《国际发展与全球生态学杂志》2013,20(1):81-88
A better understanding of the spatial linkage between the distribution of land vulnerable to degradation and long-term population growth may contribute to sustainable land management of dry regions. Such a nexus has received increasing attention among politicians and local stakeholders, as its complex outcomes depend on mutual interactions between socioeconomic and biophysical factors. This is particularly true in southern Europe, where important processes of land degradation (LD) have been observed in recent years. This paper analyses population growth (1871–2007) in southern Italy and questions its relationship with the level of land vulnerable to degradation. Results indicate that vulnerable lands were more likely associated with areas where population growth has determined environmental pressures on coastal areas and the neighbouring lowlands during 1950–1980. This pattern consolidated the socioeconomic polarisation between core and peripheral areas. Since the 1980s, however, southern Italy has experienced a phase of polycentric development, possibly determining a ‘decoupling’ between population density and land vulnerability to degradation. Population increased in moderately vulnerable areas but decreased in highly vulnerable areas. The policy implications of these results are discussed. 相似文献