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121.
The financial costs of recycling schemes fail to account for external costs and benefits such as environmental pollution, road congestion and accidents. This paper compares the environmental and social impacts of a kerbside collection scheme for recyclable household waste, with a bring scheme, using lifecycle assessment. Economic valuation is used to assign relative weights to these impacts. A second comparison examines the relative external costs of recycling and landfill disposal of waste. The results show that the kerbside collection scheme has a lower external cost than the bring scheme, but this is of less importance than the benefits to be gained within the manufacturing system by using secondary materials. It is concluded that the combination of lifecycle assessment and economic valuation is an effective means of evaluation to direct the sustainable development of waste management.  相似文献   
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123.
In the United Kingdom, as with other European countries, land-based emissions of NOx and SO2 have fallen significantly over the last few decades. SO2 emissions fell from a peak of 3185 Gg S in 1970 to 344 Gg S in 2005 and are forecast by business-as-usual emissions scenarios to fall to 172 Gg by 2020. NOx emissions were at a maximum of 951 Gg N in 1970 and fell to 378 by 2005 with a further decrease to 243 Gg N forecast by 2020. These large changes in emissions have not been matched by emissions changes for NH3 which decreased from 315 Gg N in 1990 to 259 in 2005 and are forecast to fall to 222 by 2020. The Fine Resolution Atmospheric Multi-pollutant Exchange model (FRAME) has been applied to model the spatial distribution of sulphur and nitrogen deposition over the United Kingdom during a 15-year time period (1990–2005) and compared with measured deposition of sulphate, nitrate and ammonium from the national monitoring network. Wet deposition of nitrogen and sulphur was found to decrease more slowly than the emissions reductions rate. This is attributed to a number of factors including increases in emissions from international shipping and changing rates of atmospheric oxidation. The modelled time series was extended to a 50-year period from 1970 to 2020. The modelled deposition of SOx, NOy and NHx to the UK was found to fall by 87%, 52% and 25% during this period. The percentage area of sensitive habitats in the United Kingdom for which critical loads are exceeded is estimated to fall from 85% in 1970 to 37% in 2020 for acidic deposition and from 73% to 49% for nutrient nitrogen deposition. The significant reduction in land emissions of SO2 and NOx focuses further attention in controlling emissions from international shipping. Future policies to control emissions of ammonia from agriculture will be required to effect further significant reductions in nitrogen deposition.  相似文献   
124.
黑碳(BC)气溶胶来源复杂且具有特殊环境和气象影响效应.我国不同大气环境下的BC时空分布特征亟待全面认识.使用2006~2020年中国7个大气本底站长期BC观测数据,结合气象数据、排放源、增强植被指数(EVI)和气溶胶光学厚度(AOD)数据,综合分析了BC的时空分布特征、长期演化趋势及其影响因素.结果表明,中国不同地区的BC浓度和AOD差异较大,BC对AOD多为正贡献.受排放源和气象条件等因素的影响,BC浓度和AOD空间分布为东高西低,"胡焕庸线"以东的龙凤山、上甸子、临安和金沙的浓度较高,ρ(BC)和AOD平均值分别为(1699±2213)~(3392±2131) ng·m-3和0.36±0.32~0.72±0.37;"胡焕庸线"以西的阿克达拉、瓦里关和香格里拉的浓度较低,ρ(BC)和AOD平均值分别为(287±226)~(398±308) ng·m-3和0.20±0.13~0.22±0.19.不同大气本底站BC的年际变化可分为4类:年际变化较小型,主要为阿克达拉站;先增后减然后稳定型,主要为瓦里关站;先降低后稳定类,主要为香格里拉站;先稳定后降低型,主要为龙凤山、上甸子、金沙和临安.不同大气本底站BC的季节变化具有差异."胡焕庸线"以西地区秋季BC浓度最低,冬季和春季BC浓度较高;"胡焕庸线"以东地区冬季BC浓度最高,夏季BC浓度最低.BC对AOD的影响在"胡焕庸线"东西部站点的春季和夏季均较大,在"胡焕庸线"以西站点的秋季较小,在"胡焕庸线"以东站点的冬季较小.大气本底站BC的日变化多为双峰型分布,但是峰值时间存在显著地区和季节差异.  相似文献   
125.
126.
There are two approaches in the application of satellite sensors to marine pollution studies. Satellite sensors are used to observe and characterize ocean pollutants such as industrial wastes and oil. in addition, satellite observations provide information useful in illuminating processes such as eutrophi-cation or air-sea exchange of CO2, that are important in determining the distribution and fate of pollutants.

Satellite technology is an important tool in monitoring and studying ocean pollution. Visible sensors have been used to observe and characterize sewage sludge and industrial wastes dumped at sea. Oil slicks have been observed with Landsat, AVHRR and SAR imagery. Besides directly detecting pollutants, satellite sensors are useful for analyzing ocean processes that are influential in the fate of pollutants. These processes include eutrophication of coastal waters and the distribution of suspended matter. the fate of excess CO2 can be addressed using scatterometer-derived estimates of wind speeds to determine the CO2 exchange coefficient at the sea surface on a global scale.  相似文献   
127.
In recent decades, dozens of studies have involved attempts to introduce native and desirable nonnative plant species into grasslands dominated by invasive weeds. The newly introduced plants have proved capable of establishing, but because they are rarely monitored for more than four years, it is unknown if they have a high likelihood of persisting and suppressing invaders for the long-term. Beyond invaded grasslands, this lack of long-term monitoring is a general problem plaguing efforts to reintroduce a range of taxa into a range of ecosystems. We introduced species from seed and then periodically measured plant abundances for nine years at one site and 15 years at a second site. To our knowledge, our 15-year data are the longest to date from a seeding experiment in invaded, never-cultivated grassland. At one site, three seeded grasses maintained high densities for three or more years, but then all or nearly all individuals died. At the second site, one grass performed similarly, but two other grasses proliferated and at least one greatly suppressed the dominant invader (Centaurea maculosa). In one study, our point estimate suggests that the seeded grass Thinopyrum intermedium reduced C. maculosa biomass by 93% 15 years after seeding. In some cases, data from three and fewer years after seeding falsely suggested that seeded species were capable of persisting within the invaded grassland. In other cases, data from as late as nine years after seeding falsely suggested seeded populations would not become large enough to suppress the invader. These results show that seeded species sometimes persist and suppress invaders for long periods, but short-term data cannot predict if, when, or where this will occur. Because short-term data are not predictive of long-term seeded species performances, additional long-term data are needed to identify effective practices, traits, and species for revegetating invaded grasslands.  相似文献   
128.
Experiencing uncivil customers is a frequent reality for many people working in the service industry. Past research has established that dealing with uncivil customers can be distressing for employees and can sometimes lead them to engage in reciprocal, discourteous behavior. The purpose of our research is to delve deeper into the experience of customer incivility from the perspective of service employees in order to better understand the various ways in which they respond to customer incivility. We conducted 64 interviews with service employees across an array of occupations and developed a typology of responses to customer incivility. These responses fell into four categories based on the extent to which service employees' actions were intended to promote social harmony (and therefore could broadly be considered civil or uncivil), as well as their perceived agency in the situation. We describe how each response was associated with different interpersonal and intrapersonal consequences and explain the implications of our typology for management theory and practice.  相似文献   
129.
Evaluating the effects of fishing and environmental factors on fish populations are fundamental tenets of fisheries science. In this study, we assess associations between environmental variables (sea surface temperature; North Atlantic Oscillation index; upwelling; wind magnitude; westerly winds; northerly winds; river discharge) and fishing variables (fishing effort) in Diplodus sagus catch rates accounting for regional analyses (northwest coast; southwest coast and Algarve—Algarve south coast). Different time series models for data fitting (multi-model approach) were used. The models were lagged, according to species fishing recruitment age based on the hypothesis that fisheries catches depend on larvae recruitment and survivorship. D. sargus catch rates across areas were unrelated to fishing effort but correlated to environmental variables, with seasonal events explaining much of the variability in trends. On the northwestern coast, the catch rates were mainly set by sea surface temperature (SST) and wind magnitude; however, southwestern coast catch rates were set by NAO winter. On the south coast, only one statistical model (SST, upwelling and westerly winds) associated spring conditions with D. sargus catch rates. The multi-model approach revealed autumn, winter and spring seasonal effects to be related with northwest, southwest and Algarve coastal catch rates, respectively, indicating a possible coastal longitudinal gradient related with given periods of spawning and larval availability. The metadata analysis yielded different results from the regional analyses. In summary, marine resource management should take regional environment characteristics and variability into account when determining sustainable catch rates in given areas for species with high habitat site fidelity.  相似文献   
130.
The growing importance of the environment and its management has simultaneously emphasized the benefits of hydroelectric power and its environmental costs. In a changing policy climate, giving importance to renewable energy development and environmental protection, conflict potential between stakeholders is considerable. Navigation of conflict determines the scheme constructed, making sustainable hydropower a function of human choice. To meet the needs of practitioners, greater understanding of stakeholder conflict is needed. This paper presents an approach to illustrate the challenges that face small-scale hydropower development as perceived by the stakeholders involved, and how they influence decision-making. Using Gordleton Mill, Hampshire (UK), as an illustrative case, soft systems methodology, a systems modeling approach, was adopted. Through individual interviews, a range of problems were identified and conceptually modeled. Stakeholder bias towards favoring economic appraisal over intangible social and environmental aspects was identified; costs appeared more influential than profit. Conceptual evaluation of the requirements to meet a stakeholder-approved solution suggested a complex linear systems approach, considerably different from the real-life situation. The stakeholders introduced bias to problem definition by transferring self-perceived issues onto the project owner. Application of soft systems methodology caused a shift in project goals away from further investigation towards consideration of project suitability. The challenge of sustainable hydropower is global, with a need to balance environmental, economic, and social concerns. It is clear that in this type of conflict, an individual can significantly influence outcomes; highlighting the need for more structured approaches to deal with stakeholder conflicts in sustainable hydropower development.  相似文献   
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