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1.
Permafrost and changing climate: the Russian perspective   总被引:2,自引:0,他引:2  
Anisimov O  Reneva S 《Ambio》2006,35(4):169-175
The permafrost regions occupy about 25% of the Northern Hemisphere's terrestrial surface, and more than 60% of that of Russia. Warming, thawing, and degradation of permafrost have been observed in many locations in recent decades and are likely to accelerate in the future as a result of climatic change. Changes of permafrost have important implications for natural systems, humans, and the economy of the northern lands. Results from mathematical modeling indicate that by the mid-21st century, near-surface permafrost in the Northern Hemisphere may shrink by 15%-30%, leading to complete thawing of the frozen ground in the upper few meters, while elsewhere the depth of seasonal thawing may increase on average by 15%-25%, and by 50% or more in the northernmost locations. Such changes may shift the balance between the uptake and release of carbon in tundra and facilitate emission of greenhouse gases from the carbon-rich Arctic wetlands. Serious public concerns are associated with the effects that thawing permafrost may have on the infrastructure constructed on it. Climate-induced changes of permafrost properties are potentially detrimental to almost all structures in northern lands, and may render many of them unusable. Degradation of permafrost and ground settlement due to thermokarst may lead to dramatic distortions of terrain and to changes in hydrology and vegetation, and may lead ultimately to transformation of existing landforms. Recent studies indicate that nonclimatic factors, such as changes in vegetation and hydrology, may largely govern the response of permafrost to global warming. More studies are needed to better understand and quantify the effects of multiple factors in the changing northern environment.  相似文献   

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In recent years numerous investigations have examined the relationships between chronic ozone (O(3)) exposure and plant responses using statistical or empirical cause-effect models. One of the critically important decisions underlying these studies has been the choice of the control or reference O(3) exposure to which all other treatments are compared. The issue of the control or reference O(3) exposure is a complex one. Does a single ambient control or reference O(3) exposure exist? The approach taken in this paper is to examine the O(3) concentrations in the 'clean troposphere.' One must ask what a clean troposphere is and whether there are any geographic locations in the world today that are totally free of human influences. Data on photochemical oxidants from Fortress Mountain, Alberta, Canada, are examined. A comparison of these data with air quality data from other locations in North America is used to examine the design of vegetation response studies. The need for integrated research design, execution, and evaluation is stressed.  相似文献   

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Although it is commonplace today to argue that population growth drives many or most environmental problems, Jane Jacobs has questioned the prevailing view, noting that the empirical evidence for it is actually rather slim. This article presents a case study of the pressures that population places on water in the Middle East, concluding that the countries of the region suffer from inappropriate patterns of water use rather than from excessive population. Heavy reliance on agriculture for employment or to earn foreign exchange can only lead to environmental collapse in such an arid region. In particular, to develop export markets for agricultural products is really to export water from a water-poor region. With such short-sighted policies in place, the region has already entered upon a severe crisis of recurring and intensifying water shortages that are exacerbated by population growth. If more intelligent use were made of the waters of the region, a population considerably larger than found at present could be supported without excessive stress on water resources or the natural ecology. To accomplish this, the nations of the region must create legal institutions to enable them to undertake integrated (joint) management of their shared water resources.  相似文献   

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Diphenylamine and derivatives in the environment: a review   总被引:3,自引:0,他引:3  
Drzyzga O 《Chemosphere》2003,53(8):809-818
Diphenylamine (DPA) is a compound from the third European Union (EU) list of priority pollutants. It was assigned by the EU to Germany to assess and control its environmental risks. DPA and derivatives are most commonly used as stabilizers in nitrocellulose-containing explosives and propellants, in the perfumery, and as antioxidants in the rubber and elastomer industry. DPA is also widely used to prevent post-harvest deterioration of apple and pear crops. DPA is a parent compound of many derivatives, which are used for the production of dyes, pharmaceuticals, photography chemicals and further small-scale applications. Diphenylamines are still produced worldwide by the chemical industries. First reports showed that DPA was found in soil and groundwater. Some ecotoxicological studies demonstrated the potential hazard of various diphenylamines to the aquatic environment and to bacteria and animals. Studies on the biodegradability of DPA and its derivatives are very sparse. Therefore, further investigation is required to determine the complete dimension of the potential environmental hazard and to introduce possible (bio)remediation techniques for sites that are contaminated with this class of compounds. This is the first detailed review on DPA and some derivatives summarizing their environmental relevance as it is published in the literature so far and this review will recommend conducting further research in the future.  相似文献   

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Environmental Science and Pollution Research - Phosphorus is one of the main nutrients required for all life. Phosphorus as phosphate form plays an important role in different cellular processes....  相似文献   

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Manifold linkages exist between climate change and sustainable development. Although these are starting to receive attention in the climate exchange literature, the focus has typically been on examining sustainable development through a climate change lens, rather than vice versa. And there has been little systematic examination of how these linkages may be fostered in practice. This paper examines climate change through a sustainable development lens. To illustrate how this might change the approach to climate change issues, it reports on the findings of a panel of business, local government, and academic representatives in British Columbia, Canada, who were appointed to advise the provincial government on climate change policy. The panel found that sustainable development may offer a significantly more fruitful way to pursue climate policy goals than climate policy itself. The paper discusses subsequent climate change developments in the province and makes suggestions as how best to pursue such a sustainability approach in British Columbia and other jurisdictions.  相似文献   

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The COVID-19 pandemic has brought profound social, political, economic, and environmental challenges to the world. The virus may have emerged from wildlife reservoirs linked to environmental disruption, was transmitted to humans via the wildlife trade, and its spread was facilitated by economic globalization. The pandemic arrived at a time when wildfires, high temperatures, floods, and storms amplified human suffering. These challenges call for a powerful response to COVID-19 that addresses social and economic development, climate change, and biodiversity together, offering an opportunity to bring transformational change to the structure and functioning of the global economy. This biodefense can include a “One Health” approach in all relevant sectors; a greener approach to agriculture that minimizes greenhouse gas emissions and leads to healthier diets; sustainable forms of energy; more effective international environmental agreements; post-COVID development that is equitable and sustainable; and nature-compatible international trade. Restoring and enhancing protected areas as part of devoting 50% of the planet’s land to environmentally sound management that conserves biodiversity would also support adaptation to climate change and limit human contact with zoonotic pathogens. The essential links between human health and well-being, biodiversity, and climate change could inspire a new generation of innovators to provide green solutions to enable humans to live in a healthy balance with nature leading to a long-term resilient future.  相似文献   

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Simultaneous measurements of the PM concentration levels and chemical composition of atmospheric aerosols at a regional background (RB) and an urban background (UB) site, located in the same geographic region, allowed for the determination of their urban and regional contributions. In the specific case of the North-Western region of the Mediterranean the RB amount has been quantified in 18, 13 and 12 μg m?3 for PM10, PM2.5 and PM1, respectively, whereas the UB contribution reached 22, 13 and 8 μg m?3, respectively. The UB contributions in the Western Mediterranean are much higher than those observed in other European regions; especially concerning the coarse fraction. The high loads of road dust in the urban areas across the Mediterranean may account for these large differences.The urban contributions are extremely enriched in Ca, Fe, Sb, Sn, Cu, Zn, being the main tracers of the road dust, with concentrations up to 6–8 times higher than those at the RB. Elemental carbon and nitrate are mainly derived from direct vehicular emissions. Some industrial tracers (Mn, Pb, Bi) are also enriched in the urban area. The evaluation of the Cu/Sb, Cu/Zn, Cu/Cd and Cu/Pb ratios and the high enrichment of these trace elements versus the Upper Crustal Composition average values corroborates the importance of the road-traffic emissions in the study area, also influencing the RB.The supplementary results from a suburban site in the Balearic Islands and the evaluation of the V/Ni ratios evidence the strong signature of fuel-oil combustion processes, which is a general characteristic of the Mediterranean aerosols.  相似文献   

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Between November 1995 and October 1996, particulate matter concentrations (PM10 and PM2.5) were measured in 25 study areas in six Central and Eastern European countries: Bulgaria, Czech Republic, Hungary, Poland, Romania and Slovak Republic. To assess annual mean concentration levels, 24-h averaged concentrations were measured every sixth day on a fixed urban background site using Harvard impactors with a 2.5 and 10 μm cut-point. The concentration of the coarse fraction of PM10 (PM10−2.5) was calculated as the difference between the PM10 and the PM2.5 concentration. Spatial variation within study areas was assessed by additional sampling on one or two urban background sites within each study area for two periods of 1 month. QA/QC procedures were implemented to ensure comparability of results between study areas. A two to threefold concentration range was found between study areas, ranging from an annual mean of 41 to 98 μg m−3 for PM10, from 29 to 68 μg m−3 for PM2.5 and from 12 to 40 μg m−3 for PM10−2.5. The lowest concentrations were found in the Slovak Republic, the highest concentrations in Bulgaria and Poland. The variation in PM10 and PM2.5 concentrations between study areas was about 4 times greater than the spatial variation within study areas suggesting that measurements at a single sampling site sufficiently characterise the exposure of the population in the study areas. PM10 concentrations increased considerably during the heating season, ranging from an average increase of 18 μg m−3 in the Slovak Republic to 45 μg m−3 in Poland. The increase of PM10 was mainly driven by increases in PM2.5; PM10−2.5 concentrations changed only marginally or even decreased. Overall, the results indicate high levels of particulate air pollution in Central and Eastern Europe with large changes between seasons, likely caused by local heating.  相似文献   

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Chen L  Zhou HY  Deng QY 《Chemosphere》2007,68(2):354-359
The photolysis of nonylphenol ethoxylates with an average oligomers length of ten ethoxylate units (NPEO(10)) in aqueous solution under UV, as well as the influence of humic acid (HA) on the photolysis was studied. A 125W high-pressure mercury lamp was employed as the light source. The intermediate products from the photolysis were determined by LC-MS. The results indicated that NPEO(10) underwent direct photolysis upon exposed to UV. The degradation pathway was complex. Besides the generally proposed degradation pathway of ethylene oxide (EO) side chains shortening, the oxidation of alkyl chain and EO chain led to intermediates having both a carboxylated (as well as carbonylated) ethoxylate and alkyl chain of varying lengths. The hydrogenation of benzene ring was also detected. The kinetics data showed that the first order reaction kinetics could be well used to describe the kinetics of NPEO(10) degradation. In the presence of dissolved organic matter by HA addition, the performance of NPEO(10) photodegradation was reduced. The photolysis rate decreased with increased HA concentration.  相似文献   

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Dioxins and furans (PCDD/Fs), polychlorobiphenyls (PCBs) and hexachlorobenzene (HCB) in the ecosystem of the Lagoon of Venice were studied, in order to provide a general picture of conditions in the lagoon in terms of contamination by persistent organic pollutants (POPs). We present here novel data on atmospheric deposition, water, sediment and clam samples collected in the lagoon during the period January 2001-December 2004. Atmospheric deposition was sampled monthly at six sites located both close and far from large industrial and urban sources. Water samples were collected monthly from fifteen stations, and twenty-five samples of sediments and clams (Tapes philippinarum) were collected in four areas where clams are farmed and harvested inside the lagoon. All samples were analysed for PCDD/Fs, PCBs and HCB by HRGC/HRMS in the same laboratory. All samples examined (atmospheric deposition and water) substantially confirmed the spatial pattern reported in previously published data on sediments and atmospheric deposition: the zone surrounding the Porto Marghera petrochemical plant always had the highest levels of POPs (i.e., PCDD/Fs: atmosphere approximately 6 pg of 2,3,7,8-TCDD equivalents (I-TE) m(-2)d(-1); water 0.37 pg I-TEl(-1); sediment: 300 ng kg(-1); clam 2.8 pg I-TE g(-1)), and the minima were found at points on the margins of the lagoon (PCDD/Fs: atmosphere approximately 1 pg I-TEm(-2)d(-1); water 0.05 pg I-TEl(-1); sediment: approximately 5 ng kg(-1); clam approximately 0.2 pg I-TE g(-1)). Intermediate values were often encountered in the historical city centre of Venice and in the central part of the lagoon. To confirm this, new data on correlation between levels of PCDD/F in sediments and clams are reported, both for absolute values and for the PCDD/F "fingerprint". There is always a clear fingerprinting signature (PCDF/PCDD>1) for samples collected near Porto Marghera, and the opposite (PCDF/PCDD<1) in the rest of the lagoon.  相似文献   

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《Chemosphere》1986,15(7):825-860
The consequences of contamination of the aquatic environment by chlorophenols (2-chlorophenol, 3-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol), have been evaluated by extensive review of the available scientific data. The chlorophenols generally exert moderate toxic effects to mammalian and aquatic life, although toxicity to fish upon long-term exposure may be considerable, as has been found for 2,4-dichlorophenol. Persistence is low when adapted microflora is present, capable of biodegrading these compounds, but may become moderate to high depending on the environmental conditions. This is most pronounced for 3-chlorophenol. Bioaccumulation is expected to be low. A striking feature of these chlorophenols is their strong organoleptic effect.  相似文献   

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