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494.
Mestres R 《Environmental science and pollution research international》2005,12(3):128-132
Background and Goal The object of Green Chemistry is the reduction of chemical pollutants flowing to the environment. The Chemistry and the Environment Division of EuCheMS has assumed Green Chemistry as one of its areas of interest, but one question to solve is where Green Chemistry should be placed within the context of Chemistry and the Environment. The concept of Green Chemistry, as primarily conceived by Paul Anastas and John Warner, is commonly presented through the Twelve Principles of Green Chemistry. However, these Twelve Principles, though fruit of a great intuition and common sense, do not provide a clear connection between aims, concepts, and related research areas of Green Chemistry. These two unsolved questions are the object of the present article.Discussion Green Chemistry is here placed as a part of Chemistry for the Environment, concerning the still non-existent pollutants. Indeed, the object of Green Chemistry is the reduction of pollution and risks by chemicals by avoiding their generation or their introduction into the biosphere. The distinction between pollutant chemicals and dangerous chemicals, along with the consideration of the exhaustion of fossil resources and the acknowledgement of the harmful effects of the chemicals employed in a great variety of activities, leads to the recognition of four general objectives for Green Chemistry. In order to accomplish these general objectives, a number of strategies, or secondary objectives and some fundamental concepts, namely, atomic economy, selectivity, potential harm or historical harm can be visualized. A connection is finally established between the strategies and current and future research areas of Green Chemistry.Conclusion The ultimate aim of green chemistry is to entirely cut down the stream of chemicals pouring into the environment. This aim seems unattainable at present, but progress in the green chemical research areas and their application through successive approaches will certainly provide safer specialty chemicals and much more satisfactory processes for the chemical industry.- * The basis of this peer-reviewed paper is a presentation at the 9th FECS Conference on Chemistry and Environment, 29 August to 1 September 2004, Bordeaux, France. 相似文献
495.
Klöpffer W 《Environmental science and pollution research international》2005,12(3):173-177
Background LCA is the only internationally standardized environmental assessment tool (ISO 14040-43) for product systems, including services and processes. The analysis is done from cradle-to-grave, i.e. over the whole life cycle. LCA is essentially a comparative method: different systems fulfilling the same function (serving the same purpose) are compared on the basis of a functional unit - a quantitative measure of this function or purpose. It is often believed that LCA can be used for judging the (relative) sustainability of product systems. This is only partly true, however, since LCA is restricted to the environmental part of the triad environment/ecology - economy - social aspects (including intergenerational fairness) which constitutes sustainability. Standardized assessment tools for the second and the third part are still lacking, but Life Cycle Costing (LCC) seems to be a promising candidate for the economic part. Social Life Cycle Assessment still has to be developed on the basis of known social indicators.Method and Limitations LCA is most frequently used for the comparative assessment or optimization analysis of final products. Materials and chemicals are difficult to analyse from cradle-to-grave, since they are used in many, often innumerable product systems, which all would have to be studied in detail to give a complete LCA of a particular material or substance! This complete analysis of a material or chemical is evidently only possible in such cases where one main application exists. But even if one main application does exist, e.g. in the case of surfactants (chemicals) and detergents (final products), the latter may exist in a great abundance of compositions. Therefore, chemicals and materials are better analysed from cradle-to-factory gate, leaving the analysis of the final product(s), the use phase and the end-of-life phases to specific, full LCAs.Conclusion A comparative assessment of production processes is possible, if the chemicals (the same is true for materials) produced by different methods have exactly the same properties. In this case, the downstream phases may be considered as a black box and left out of the assessment. Such truncated LCAs can be used for environmental comparisons, but less so for the (environmental) optimization analysis of a specific chemical: the phases considered as black box and left out may actually be the dominant ones. A sustainability assessment should be performed at the product level and contain the results of LCC and social assessments. Equal and consistent system boundaries will have to be used for these life cycle tools which only together can fulfil the aim of assessing the sustainability of product systems. 相似文献
496.
Schröter M Obermeier A Brüggemann D Klemm O 《Environmental science and pollution research international》2002,9(6):381-384
A ground-based Differential Absorption Lidar was employed to study the dynamics of atmospheric O3 within the planetary boundary layer of a basin in the 'Fichtelgebirge' mountains, NE Bavaria. In particular, the night-time dynamics of O3 linked to the ground were investigated. The Lidar system measured vertical profiles of O3 up to 1 km above ground. For detailed analysis of the night-time dynamics of ozone, supplementary data from three ground-based stations (measuring mixing ratios of O3 and NO(x), as well as meteorological parameters) are essential. The Lidar results could be evaluated with these data from various altitudes above the basin floor. For the station with the largest (vertical) distance to the ground-based Lidar, the agreement was very good at all times. The Lidar method proved to be useful for examining the spatial distribution of O3. The observed night-time decrease of O3 at the bottom of the basin was due to deposition and to advection of air masses containing less O3 from the mountain slopes. 相似文献
497.
Summary. Following herbivory, induced responses involving plant secondary metabolites have been reported in a number of tree species.
Although a wide range of plant secondary metabolites appear to operate as constitutive plant defences in trees belonging to
the Eucalyptus genus, no induced responses have as yet been reported following foliar-chewing insect damage. We empirically tested whether
branch defoliation (artificial and larval) of 2-year-old Eucalyptus globulus Labill. trees altered the abundance of specific plant secondary metabolites immediately (3 months after initial larval feeding)
and 8 months after the cessation of larval feeding. Metabolites assayed, included essential oils, polyphenolic groups and
foliar wax compounds and in all cases their abundance was not significantly altered by defoliation. However, the level of
foliar tannins after 3 months of larval feeding did display a trend that suggested elevated levels as the result of defoliation,
though this trend was not evident 8 months later, indicating that, if real, the response was a rapid and not a delayed induced
response. The level of foliar tannins was also negatively correlated to both average larval survival and average percentage
branch defoliation, suggesting that foliar tannins may operate as toxins and/or anti-feedants to M. privata larval feeding. 相似文献
498.
Organic synthesis is usually performed in solution to dissolve both reactants and catalysts and to deliver heat. Here, we
show that glycerol, which is a non-toxic, biodegradable, and recyclable liquid manufactured from renewable sources, has a
high potential to serve as alternative green solvent for organic reactions. Several catalytic and non-catalytic reactions
were successfully performed in glycerol. High products yields and selectivities were achieved. Besides solubility of the reactants
and the catalysts and easy separation of the product, glycerol offers several other benefits such as catalyst recycling, microwave
assisting reaction, and biphasic and emulsion modes. 相似文献
499.
Philip M. Fearnside 《Environmental management》1989,13(4):401-423
The Balbina Dam in Brazil's state of Amazonas floods 2360 km2 of tropical forest to generate an average of only 112.2 MW of electricity. The flat topography and small size of the drainage basin make output small. Vegetation has been left to decompose in the reservoir, resulting in acidic, anoxic water that will corrode the turbines. The shallow reservoir contains 1500 islands and innumerable stagnant bays where the water's residence time will be even longer than the average time of over one year. Balbina was built to supply electricity to Manaus, a city that has grown so much while the dam was under construction that other alternatives are already needed. Government subsidies explain the explosive growth, including Brazil's unified tariff for electricity. Alternative power sources for Manaus include transmission from more distant dams or from recently discovered oil and natural gas deposits. Among Balbina's impacts are loss of potential use of the forest and displacement of about one third of the surviving members of a much-persecuted Amerindian tribe: the Waimiri-Atroari. The dam was closed on 1 October 1987 and the first of five generators began operation in February 1989. The example of Balbina points to important ways that the decision-making process could be improved in Brazil and in the international funding agencies that have directly and indirectly contributed to the project. Environmental impact analyses must be completed prior to decisions on overall project implementation and must be free of influence from project proponents. The current environmental impact assessment system in Brazil, as in many other countries, has an undesirable influence on science policy, in addition to failing to address the underlying causes of environmentally destructive development processes and inability to halt irreversible projects like Balbina. 相似文献
500.
Colleen Burch Johnson T.J. Sullivan D.J. Buck 《Journal of the American Water Resources Association》1989,25(3):565-572
ABSTRACT: Topographic maps are commonly used to define populations of lakes in regional surveys of surface water quality. To illustrate the effect of different maps on that process, we compared the lakes represented on the 1:250,000-scale maps used for the Northeast Region of the Eastern Lake Survey—Phase I (ELS-I) to the lakes on a sample of large-scale maps (1:24,000 or 1:62,500). Lake areas at or near the lower limit of representation delimited “smallest-lake” values for the compared 1:250,000-scale maps. The regional median for these values was 4.5 hectares (ha) and ranged from 0.6 to 24.8 ha. Lake representation is influenced by cartographic limitations such as map scale, age, and complexity as well as the inherent variability of waterbodies (e.g., water level fluctuations or the creation of reservoirs, beaver impoundments, and oxbows). The total number of lakes on large-scale maps increased markedly as lake area decreased. Approximately 15,700 of the estimated 29,000 lakes in the EPA's Northeast Region were 1 to 4 ha in area. Because maps affect the size distribution of lakes included in a regional survey and because lake areas are thought to modify lake chemistry, maps ultimately affect the estimates of regional surface water quality. 相似文献