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991.
992.
Establishment of plans for environmental planning and management requires that a number of natural and societal factors must be taken into consideration. Insights into the inherent dynamics of nature as well as the role that past human activities have played for establishing the current condition of the landscape and the natural environment in general are essential. Many natural and man-made changes occur over time scales of decades or centuries, and these are difficult to comprehend without a historical perspective. Such a perspective can be obtained using palaeoecological studies, i.e. by geochemical and biological analyses of lake sediment and peat deposits. To illustrate the long-term dynamics of nature and particularly the role of man, we present here five case studies from Sweden concerning pollution, lake acidification, lake eutrophication, biodiversity, and landscape dynamics and conservation – topics of broad interests – and discuss benefits of including a longer time perspective in environmental management.  相似文献   
993.
Outdoor recreation and nature-based tourism represent an increasingly intensive form of land use that has considerable impacts on native ecosystems. The aim of this paper is to investigate how revegetation and management of ski runs influence soil nutrients, vegetation characteristics, and the possible invasion of nonnative plant species used in revegetation into native ecosystems. A soil and vegetation survey at ski runs and nearby forests, and a factorial experiment simulating ski run construction and management (factors: soil removal, fertilization, and seed sowing) were conducted at Ruka ski resort, in northern Finland, during 2003–2008. According to the survey, management practices had caused considerable changes in the vegetation structure and increased soil nutrient concentrations, pH, and conductivity on the ski runs relative to nearby forests. Seed mixture species sown during the revegetation of ski runs had not spread to adjacent forests. The experimental study showed that the germination of seed mixture species was favored by treatments simulating the management of ski runs, but none of them could eventually establish in the study forest. As nutrient leaching causes both environmental deterioration and changes in vegetation structure, it may eventually pose a greater environmental risk than the spread of seed mixture species alone. Machine grading and fertilization, which have the most drastic effects on soils and vegetation, should, therefore, be minimized when constructing and managing ski runs.  相似文献   
994.
Two approaches for setting ecological class boundaries, response curves and a simplified mathematical boundary-setting protocol, were tested for coastal, transitional and open waters in the Gulf of Riga, Baltic Sea. The simplified mathematical boundary-setting protocol defines acceptable ecological status based on expert judgment by a uniform relative deviation from reference conditions. In contrast, response curves derive class boundary definitions from observed changes in biological quality elements along environmental pressure gradients for class boundary definitions. Identification of relevant environmental pressures for the construction of response curves was based on a conceptual model of eutrophication in the Gulf of Riga. Response curves were successfully established for summer chlorophyll a and transparency, as well as for macrozoobenthos abundance in the Central Gulf, macrozoobenthos biotic coefficient in the Southern Gulf, and maximum depth of phytobenthos in the Northern Gulf. In the Gulf of Riga response curves almost always permitted a larger deviation from reference conditions than the 50% deviation applied for the simplified mathematical boundary-setting protocol. The case study clearly demonstrated that class boundary definitions should take into account the sensitivity of the target water body. Also, the class boundaries for different ecological quality elements were internally more consistent than those derived by the simplified mathematical boundary-setting protocol.  相似文献   
995.
The concentration of dissolved reactive phosphorus (DRP) in rivers can change intermittently within minutes depending on the weather and water discharge (Q), or activities in the watershed. Accordingly, accurate estimation of the annual DRP load requires frequent sampling or even continuous monitoring, which is laborious and cost-intensive. We present the design and laboratory evaluation of a new, robust, low-cost, low-tech device based on passive samplers (P-traps). The traps use Fe-(oxy)hydroxide coated quartz sand as an adsorbent enclosed in a vertical grid of individual cells separated from the river water by filter membranes. They are inexpensive, easy to handle, resistant to repeated desiccation and immersion and exposable for several months. They permit estimation of discharge dependent time weighted average DRP concentrations (C-Q relationships) and annual P loads of rivers characterized by highly variable DRP concentrations with a relative accuracy of +/- 3%.  相似文献   
996.
The air quality over the Toulouse urban area (France) is recorded daily by the regional "Midi-Pyrénées" atmospheric pollution measurements network (ORAMIP). Relevant data is collected from about 100 analysers spread over more than thirty stations. The regulations covering major indicators of atmospheric pollution (ozone, nitrogen dioxide, sulphur dioxide) have been updated in recent years to include additional compounds like polycyclic aromatic hydrocarbons (PAHs). The ORAMIP, in partnership with the ENSIACET has undertaken background PAH average concentration measurements over the urban agglomeration of Toulouse during spring 2006 for various types of sites (traffic, urban, industrial). The sampling was performed using a low volume air sampler equipped with quartz fiber filters and polyurethane foams For the two urban sites, total atmospheric concentrations between 12 and 20 ng/m(3) have been obtained, whereas for the industrial site the values averaged 22 ng/m(3). In addition, and regardless of site, the average concentrations of benzo[a]pyrene, at present the only regulated PAH, were always less than the 1 ng/m(3) limit.  相似文献   
997.
Man-made and natural radionuclides in Lake Wallersee were determined in the pre-Alpine environment at the northern slope of the Alps, which was heavily affected by the Chernobyl fallout in May 1986. The objective of this study was to get knowledge of location and quantity of man-made radionuclide input (especially (137)Cs) generated in the Chernobyl accident to lake sediments. Eleven sediment cores were sampled and activity depth profiles of (137)Cs and (210)Pb were determined with 5mm depth-resolution. The Chernobyl fallout produced an extreme (137)Cs peak in the sediment cores providing an excellent time marker. The chronological interpretation of deeper sediment layers was done by radiochemical analysis of (90)Sr and (239+240)Pu, which were released during atmospheric weapons' tests in the 1950s and 1960s. This allowed a complete chronological analysis of the sediment cores with a very compact set of data.  相似文献   
998.
Pharmaceuticals are designed to be bioactive and therefore are among the most important chemical compounds manufactured. In recent years pharmaceuticals have been detected in a range of environment compartments, with concerns raised that they may impose a risk to both humans and environmental organisms. To support informed management of any associated risks, knowledge about their substance flows is indispensable. However, little is known about sources and attributable substance flows with regard to the use of human pharmaceuticals. Often data available on a national level are used to judge local or regional situations and to calculate expected concentrations. In this paper, computations on the use of active pharmaceutical ingredients (APIs) of drugs used in human medicine at the local, regional and national levels were conducted. Different data sources were used and raw-data were scaled up- or downwards and compared. Results of this analysis indicated that hospitals are, by far, minor sources of pharmaceuticals to the aquatic environment in comparison to non-point emissions from households. Differences in flows at the local, regional and national scales are also identified.  相似文献   
999.
This is a study of the sources of alkylphenol and alkylphenol ethoxylates in wastewater, including the new observation that the main contribution is from textiles. Alkylphenols and alkylphenol ethoxylates are widely used chemicals in various applications that are partly under environmental restrictions within Europe. The study sets out to analyze the most important sources of this large group of organic compounds in an urban wastewater system. A substance flow analysis (SFA) of the technosphere in Stockholm, Sweden in 2004 was conducted, allowing a comparison of 13 groups of goods’ emissions to wastewater. It was found that the groups of textiles and cleaning agents were the major sources to wastewater, while the group’s personal care products and paint and lacquers give smaller contributions. The content of alkylphenol ethoxylates in goods, especially in textiles, is a most significant source and is probably valid for other urban areas as well.  相似文献   
1000.
The performance, the degradability in soil and the environmental impact of biodegradable starch-based soil mulching and low tunnel films were assessed by means of field and laboratory tests. The lifetime of the biodegradable mulches was 9 months and of the biodegradable low-tunnel films 6 months. The radiometric properties of the biodegradable films influenced positively the microclimate: air temperature under the biodegradable low tunnel films was 2 °C higher than under the low density polyethylene films, resulting in an up to 20% higher yield of strawberries. At the end of the cultivation period, the biodegradable mulches were broken up and buried in the field soil together with the plant residues. One year after burial, less than 4% of the initial weight of the biodegradable film was found in the soil. According to ecotoxicity tests, the kinetic luminescent bacteria test with Vibrio fischeri and the Enchytraeus albidus ISO/CD 16387 reproduction potential, there was no evidence of ecotoxicity in the soil during the biodegradation process. Furthermore, there was no change in the diversity of ammonia-oxidizing bacteria in the soil determined on the basis of the appearance of amoA gene diversity in denaturing gradient gel electrophoresis.  相似文献   
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