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排序方式: 共有491条查询结果,搜索用时 510 毫秒
281.
282.
Ashis Bhattacharjee Haradhan Mandal Madhusudan Roy Tapas Kumar Chini 《Environmental monitoring and assessment》2011,176(1-4):473-481
Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and tunneling electron microscopy (TEM) studies of two solid vehicle wastes (pollutants) from petrol- and diesel-fueled engines of Kolkata (India) have detected a significant amount of ultrafine particles in the nanometer scale in these wastes. Both powder XRD and selected area electron diffraction from TEM have confirmed the existence of inhomogeneous distribution of nanocrystallites in these pollutants. Energy dispersive X-ray spectrometry shows that these wastes contain mainly carbon and oxygen as the constituent components. These pollutants are magnetic in nature as seen with SQUID magnetometry, and the presence of a high amount of carbon presumably is likely the origin of the magnetic property. 相似文献
283.
A new approach to investigate the interactions between sediment transport and ecotoxicological processes during flood events 总被引:1,自引:0,他引:1
Holger Schüttrumpf Markus Brinkmann Catrina Cofalla Roy M Frings Sabine U Gerbersdorf Markus Hecker Sebastian Hudjetz Ulrike Kammann Gottfried Lennartz Sebastian Roger Andreas Schäffer Henner Hollert 《Environmental Sciences Europe》2011,23(1):1-5
Purpose
The 'step-by step' principle was introduced into the European Union legislation on genetically modified organisms as a means to cope with uncertainty about environmental risks from the release of genetically modified organisms into the environment. The approval process is orientated along the stepwise reduction of containment which reflects a precautionary approach towards the risks of genetically modified organism release. Thus, the gradual reduction of containment should keep pace with the gradual generation of risk-related knowledge. This paper strives to clarify the meaning, legal status and practical importance of the principle. It also looks at whether non-European Union countries have adopted the principle as well, and how they practice it.Methods
The article is based on research of the relevant legal texts, court cases and legal literature. In addition, a number of dossiers of applications for the European Union authorisation of release and placing on the market of genetically modified seed were analysed.Results and conclusions
Although 'step-by-step' is not a precise legal rule it does have legal meaning as a principle guiding the risk assessment and management of genetically modified organism introduction into the environment. Assuming a process of gradual reduction of containment and scaling up of release ranging from closed systems via experimental release to cultivation the 'step-by-step principle' requires that the knowledge on environmental risks of genetically modified organisms should be generated on stages previous to the ones where the risk can result in damage. The analysis of the legislation of China, the United States of America and Brazil showed a differentiated approach towards the step-by-step principle. 相似文献284.
Akter S Brouwer R van Beukering PJ French L Silver E Choudhury S Aziz SS 《Disasters》2011,35(2):287-307
This paper aims to contribute to the debate on the feasibility of the provision of micro flood insurance as an effective tool for spreading disaster risks in developing countries and examines the role of the institutional-organisational framework in assisting the design and implementation of such a micro flood insurance market. In Bangladesh, a private insurance market for property damage and livelihood risk due to natural disasters does not exist. Private insurance companies are reluctant to embark on an evidently unprofitable venture. Testing two different institutional-organisational models, this research reveals that the administration costs of micro-insurance play an important part in determining the long-term viability of micro flood insurance schemes. A government-facilitated process to overcome the differences observed in this study between the nonprofit micro-credit providers and profit-oriented private insurance companies is needed, building on the particular competence each party brings to the development of a viable micro flood insurance market through a public-private partnership. 相似文献
285.
In recent years, policy mechanisms to support a formalized artisanal and small‐scale mining (ASM) sector in sub‐Saharan Africa have gained increasing currency. Proponents of formalization argue that most social and environmental problems associated with the sector stem from the fact that ASM is predominantly unregulated and operates outside the legal sphere. This paper critically examines recent efforts to formalize artisanal and small‐scale mining in West Africa, drawing upon recent fieldwork carried out in Sierra Leone, Ghana and Mali. In exploring the sector's livelihood dimensions, the analysis suggests that bringing unregulated, informal mining activities into the legal domain remains a considerable challenge. The paper concludes by confirming the urgent need to refocus formalization strategies on the main livelihood challenges and constraints of small‐scale miners themselves, if poverty is to be alleviated and more benefits are to accrue to depressed communities in mineral‐rich regions. 相似文献
286.
Khan Pathan Mohsin Lombardo Anna Benfenati Emilio Roy Kunal 《Environmental science and pollution research international》2021,28(2):1627-1642
Environmental Science and Pollution Research - Hydrolysis is one of the most important processes of transformation of organic chemicals in water. The rates of reactions, final chemical entities of... 相似文献
287.
Benjamin Honigman Roy Cromer Thomas L. Kurt 《Journal of the Air & Waste Management Association (1995)》2013,63(1):77-79
ABSTRACT Gas phase concentrations of individual polycyclic aromatic hydrocarbons (PAHs) were measured in real time in combustion products from a co-flow diffusion flame using laser photoionization (LP) time-of-flight mass spectrometry (TOF/MS). In particular, a naphthalene detection sensitivity of 4 parts per billion (ppb) was demonstrated. The use of calibration mixtures with argon indicated the feasibility of naphthalene detection at about 45 parts per trillion (ppt) at a signal-to-noise (S/N) ratio of 20. This suggests the possibility of low-ppt level detection at a S/N of 1. The novelty of the system is the use of a heated sampling probe and a continuously purged, heated-pulse valve that was positioned close to the ionization zone, thereby allowing the generation of photoions in the high-density region of the sample jet, where concentrations of PAH are high. Because the system developed allows for the real time detection of select species, it represents a useful tool in continuous emissions monitoring (CEM) for environmental compliance as well as direct process control. 相似文献
288.
Trygve Hesthagen Bjørn Walseng Leif Roger Karlsen Roy M. Langåker 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):339-345
We studied the effects of liming on fish and crustaceans in a watershed which is in a region known to have one of the highest
diversity of aquatic biota in Norway. This watershed, Enningdal, is shared between Norway (1/3) and Sweden (2/3) and includes
61 lakes > 1.0 ha in Norway. Liming started on a large scale in the 1980s. Currently, a total of 26 of lakes (43%) are limed,
covering 93% of the total lake area. The mean value ± S.D. of pH and the concentration of inorganic labile Al in these lakes
is 6.62 ± 0.35 and 3 ± 4 μg l−1, respectively. Historical data of fish communities have been obtained from surveys, while test-fishing and sampling of crustaceans
were conducted in 24 lakes in recent years (2002–2004). The present study shows that crustaceans to a greater extent than
fish has responded to improved water quality after more than 20 years of liming. Of a total of 120 fish populations, 42 (35%)
have gone extinct. Only five of the lost fish populations (12%) have been re-established, all due to human re-introductions.
Physical barriers are considered to be the main factor preventing fish from invading limed lakes. In contrast, crustaceans
have been re-established in most limed lakes. This may be mainly due to their good spreading capacity. However, they might
also have survived in refuges within the watershed, or as resting-eggs in the sediment. 相似文献
289.
Regional Environmental Change - Despite the fact that we currently witness an increasing interest in the study of the role of agency in policy dynamics, it remains in many respects a puzzle how... 相似文献
290.
From 1935 to 2000, the net open water area of Inle Lake in Central Shan State, Myanmar decreased from 69.10 to 46.69 km2, a loss of 32.4% during this 65-year period. Local beliefs are that losses in lake area have been even greater within the
last 100–200 years. Various activities, including timber removal, shifting agriculture in the uplands by various ethnic groups,
and unsustainable cultivation practices on the low- and mid-level hillslopes around the lake, have been blamed for both historical
and ongoing sedimentation. We take issue with attributing loss of lake area to these activities, and propose instead that
ongoing “in-lake” and “near-lake” agricultural practices are the main sources of contemporary sediment and loss of open water
area. About 93% (i.e., 20.84 km2) of the recent loss in open water area of the lake is due to the development of floating garden agriculture, largely along
the west side of the lake. Direct environmental impacts associated with this practice and with other agriculture activities
within the wetlands and margins of the lake include sedimentation, eutrophication, and pollution. Whilst the sustainability
of hillslope agriculture and past forestry practices can indeed be questioned, a more urgent need is to address these "in-lake"
and "near-lake" practices. 相似文献