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121.
Iva H?nová Radek Novotný Tomáš Vráblík Bohumír Lomský 《Environmental pollution (Barking, Essex : 1987)》2010,158(7):2393-2401
Malondialdehyde (MDA), a product of lipid peroxidation and biomarker of oxidative stress, is measured over the long term in spruce Picea abies needles under real conditions in three Czech mountain border areas. The trends presented collate the MDA content in spruce needles with ambient ozone, temperature and precipitation as casual, and defoliation as a subsequent factor for the period 1994-2006. We have found the overall decreasing trends in MDA and defoliation. The highest MDA and defoliation are recorded in the Jizerske, the lowest in the Krusne hory Mts. Out of the examined variables the MDA is predicted best by mean temperature in vegetation season, median of O3 concentrations and AOT40; these three variables account for 34% of MDA1 and 36% of MDA2 variability. Our hypothesis that higher ambient O3 exposure results in higher MDA contents in P. abies needles under real conditions has not been approved. 相似文献
122.
An assessment of the benthic macroinvertebrate community was conducted to characterize the ecological recovery of a channelized
main stem and two small tributaries at the Watershed Research and Education Center (WREC, Arkansas, USA). Three other headwater
streams in the same basin were also sampled as controls and for biological reference information. A principal components analysis
produced stream groupings along an overall gradient of physical habitat integrity, with degraded reaches showing lower RBP
habitat scores, reduced flow velocities, smaller substrate sizes, greater conductivity, and higher percentages of sand and
silt substrate. The benthic macroinvertebrate assemblage at WREC was dominated by fast-reproducing dipteran larvae (midge
and mosquito larvae) and physid snails, which comprised 71.3% of the total macroinvertebrate abundance over three sampling
periods. Several macroinvertebrate assemblage metrics should provide effective targets for monitoring overall improvements
in the invertebrate assemblage including recovery towards a more complex food web (e.g., total number of taxa, number of EPT
taxa, percent 2 dominant taxa). However, current habitat conditions and the extent of existing degradation, system isolation
and surrounding urban or agricultural land-uses might affect the level of positive change to the system. We therefore suggest
a preliminary restoration strategy involving the addition of pool habitats in the system. At one pool we collected a total
of 29 taxa (dominated by water beetle predators), which was 59% of total number of taxa collected at WREC. Maintaining water-retentive
pools to collect flows and maintain water permanence focuses on enhancing known biology and habitat, thus reducing the effects
of abiotic filters on macroinvertebrate assemblage recovery. Furthermore, biological assessment prior to restoration supports
a strategy primarily focused on improving the existing macroinvertebrate community in the current context of the system, thereby
reducing costs associated with active channel restoration. Monitoring future biological recovery and determining the contribution
of changing assemblages to specific ecological processes would provide a critical underpinning for adaptive management and
ecologically-effective restoration. 相似文献
123.
This paper models the monthly price volatilities of four precious metals (gold, silver, platinum and palladium prices) and investigates the macroeconomic determinants (business cycle, monetary environment and financial market sentiment) of these volatilities. Gold volatility is shown to be explained by monetary variables, but this is not true for silver. Overall, there is limited evidence that the same macroeconomic factors jointly influence the volatility processes of the four precious metal price series, although there is evidence of volatility feedback between the precious metals. These results are consistent with the view that precious metals are too distinct to be considered a single asset class, or represented by a single index. This finding is of importance for portfolio managers and investors. 相似文献
124.
Skene KJ Gent JF McKay LA Belanger K Leaderer BP Holford TR 《Atmospheric environment (Oxford, England : 1994)》2010,44(39):5156-5164
An integrated exposure model was developed that estimates nitrogen dioxide (NO(2)) concentration at residences using geographic information systems (GIS) and variables derived within residential buffers representing traffic volume and landscape characteristics including land use, population density and elevation. Multiple measurements of NO(2) taken outside of 985 residences in Connecticut were used to develop the model. A second set of 120 outdoor NO(2) measurements as well as cross-validation were used to validate the model. The model suggests that approximately 67% of the variation in NO(2) levels can be explained by: traffic and land use primarily within 2 km of a residence; population density; elevation; and time of year. Potential benefits of this model for health effects research include improved spatial estimations of traffic-related pollutant exposure and reduced need for extensive pollutant measurements. The model, which could be calibrated and applied in areas other than Connecticut, has importance as a tool for exposure estimation in epidemiological studies of traffic-related air pollution. 相似文献
125.
126.
Restoration of acidified lakes by liming does not, in many cases, improve productivity to a pre-acidified state. We hypothesize that the poor recovery detected in many of these lakes is due to constrained in-lake phosphorous (P) cycling caused by enhanced precipitation of metals in higher pH, limed waters. Long-term (1990–2012) data for 65 limed, circum-neutral (pH 6–8), and acidified lakes in Sweden were analyzed to determine trends for P and potential drivers of these trends. Limed lakes not only had lower mean values and stronger decreasing trends for total P than non-limed lakes, but they also had the highest percentage of decreasing trends (85 %). A P release factor (Hypolimnetic P/Epilimnetic P) was developed to elucidate differences in internal P cycling between lake groups. Consistently, lower P release factors in limed lakes show limitation of internal P cycling during summer months that may be a factor limiting P bioavailability and thus productivity of these systems. 相似文献
127.
Kishor Atreya Fred H?kon Johnsen Bishal Kumar Sitaula 《Environment, Development and Sustainability》2012,14(4):477-493
There is a growing concern of pesticide risks to human health, natural environment and ecosystems. Many previous economic valuations have accounted health aspects or environmental components, but rarely combined; thus, overall risk assessment is partially distorted. The study, conducted close to the capital of Nepal, addressed the health effects of pesticides on small-scale farmers and evaluated the monetary risks of pesticide use on human health and environmental resources. We also aim to establish the relationships among valuation methods. The paper adopts cost of illness, defensive expenditure and contingent valuation willingness to pay approach. The study concluded that the methods used for valuing pesticide risks to human and environmental health are theoretically consistent. The exposed individuals are likely to bear significant economic costs of exposures depending on geographical location, pesticide use magnitudes and frequency. Individuals are willing to pay between 53 and 79% more than the existing pesticide price to protect their health and environment. The integrated pest management training is less likely to reduce health costs of pesticide exposure, although it leads to higher investment in safety measures. 相似文献
128.
There is much discussion within the sustainable development community regarding climate stabilization and particularly, finding
environmentally equitable ways to address emission reductions. Knowing the current level of emission is only one variable
in this complex picture. While the rate of emissions is clearly a problem, the overall increase in GHG concentration in the
atmosphere is ultimately the main driver of anthropogenic warming. Therefore, it is also important to understand the cumulative
emissions, those which have taken us to the current condition. This research presents a case study of six countries to compare
the emissions per capita and cumulative emissions during the past 200 years. It is known that carbon emissions are closely
related to economic activities, but here we show that some countries have reached per capita emissions plateaus at different
levels while others are still rising. Specifically, one approach toward socioeconomic development, in terms of energy–economy,
reaches a plateau at 10 Mt carbon per person, which the United Kingdom and South Korea have attained. The US occupies another
emission regime at 20 Mt carbon per person. Developing economies such as India and China are considerably below these levels,
and unless they follow other integrated economic/environmental solutions, they will continue to increase their per capita
emissions during development. 相似文献
129.
In industrialized countries, the idea of degrowth has emerged as a response to environmental, social, and economic crises.
Realizing environmental limits to and failures of more than half a century of continual economic growth in terms of social
progress and environmental sustainability, the degrowth paradigm calls for a downscaling of consumption and production for
social equity and ecological sustainability. The call for economic degrowth is generally considered to be delimited to rich
countries, where reduced consumption can save “ecological space” enabling people in poor countries to enjoy the benefits of
economic growth. China, as one of the economically most expanding countries in the world, has dramatically improved its living
standards, particularly along the Eastern coast, over the latest 30 years. However, China is absent from the international
debates on growth. This article discusses the implications of the Western degrowth debates for China. Given the distinctive
features of China’s development, the paper aims to enrich the degrowth debates, which have hitherto been dominated by Western
perspectives. Based upon reflections on social, environmental, and moral dimensions of economic growth, the paper argues that
limited natural resources may not continuously support universal affluence at the current level of the rich countries, a level
that China is likely to reach within a few decades. Priority for growth in China should therefore be given to the poor regions
of the country, and future growth should be beneficial to social and environmental development. 相似文献
130.
Brian P. Leaderer Theodore R. Holford Jan A. J. Stolwijk 《Journal of the Air & Waste Management Association (1995)》2013,63(2):154-157
A PM10 monitoring network was established throughout the South Coast Air Basin (SOCAB) in the greater Los Angeles region during the calendar year 1986. Annual average PM10 mass concentrations within the Los Angeles metropolitan area ranged from 47.0 µg m-3 along the coast to 87.4 µg m-3 at Rubldoux, the furthest inland monitoring station. Measurements made at San Nicolas Island suggest that regional background aerosol contributes between 28 to 44 percent of the PM10 aerosol at monitoring sites In the SOCAB over the long term average. Five major aerosol components (carbonaceous material, NO- 3, SO= 4, NH+ 4, and soil-related material) account for greater than 80 percent of the annual average PM10 mass at all on-land monitoring stations. Peak 24-h average mass concentrations of nearly 300 µg m-3 were observed at inland locations, with lower peak values (?130–150 µg m-3) measured along the coast. Peak-day aerosol composition was characterized by increased NO- 3 Ion and associated ammonium ion levels, as compared to the annual average. There appears to be only a weak dependence of PM10 mass concentration on season of the year. This lack of a pronounced seasonal dependence results from the complex and contradictory seasonal variations in the major chemical components (carbonaceous material, nitrate, sulfate, ammonium ion and crustal material). At most sites within the Los Angeles metropolitan area, PM10 mass concentrations exceeded both the annual and 24-h average federal and state of California PM10 regulatory standards. 相似文献