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791.
Polychlorinated naphthalenes in urban soils: analysis,concentrations, and relation to other persistent organic pollutants 总被引:12,自引:0,他引:12
We determined the concentrations of 35 PCNs, 12 PCBs, and 20 PAHs in 49 urban topsoils under different land use (house garden, roadside grassland, alluvial grassland, park areas, industrial sites, agricultural sites) and in nine rural topsoils. The sums of concentrations of 35 PCNs (sigma35 PCNs) were <0.1-15.4 microg kg(-1) in urban soils and <0.1 to 0.82 microg kg(-1) in rural soils. The PCN, PCB, and PAH concentrations were highest at industrial sites and in house gardens. While rural soils receive PCNs, PCBs, and PAHs by common atmospheric deposition, there are site-specific sources of PCNs, PCBs, and PAHs for urban soils such as deposition of contaminated technogenic materials. The PCN, PCB, and PAH concentrations decreased from the central urban to the rural area. In the same order the contribution of lower chlorinated PCNs and PCBs increased because they are more volatile and subject to increased atmospheric transport. The PCNs 52+60, and 73 were more abundant in soil samples than in Halowax mixtures, indicating that combustion contributed to the PCN contamination of the soils. 相似文献
792.
The influence of dissolved humic substances on the transport of (4-chloro-2-methylphenoxy) acetic acid (MCPA) in a sandy soil with a low organic carbon content was studied in a column experiment. Soil columns were eluted with aqueous solutions containing different fractions of humic substances. More than 70% of the applied compound was found in the leachate in all sandy soil experiments, but distinct differences were obtained depending on the composition of the eluent. The addition of both humic and fulvic acids to the eluent affected the leaching behaviour of MCPA. While the presence of humic acids increased and accelerated the movement of MCPA in the investigated sandy soil, fulvic acids caused the opposite effect: increased retention was observed relative to the control. We concluded that a possible carrier transport or retention strongly depends on the composition of the dissolved organic matter. Thus, changes in the composition of dissolved organic matter may affect MCPA movement into deeper soil layers. 相似文献
793.
Martin Bradshaw 《Environmental geochemistry and health》1982,4(2-3):47-61
This paper reviews the environmental problems associated with the coal-mining industry on the Yorkshire coalfield. The main environmental problems are identified as being caused by:
- The need to dispose of large quantities of colliery waste or ‘spoil’, in an environmentally acceptable manner.
- Derelict and despoiled land, including the problems caused by the re-working of old tips for their coal content.
- Opencast coal mining.
- Subsidence.
- Transportation of coal and coal waste.
794.
Marco?B?erEmail author Charlotte?Gannefors Gerhard?Kattner Martin?Graeve Haakon?Hop Stig?Falk-Petersen 《Marine Biology》2005,147(3):707-717
During various seasons from May 2001 until July/August 2003, the lipid dynamics of the pteropod Clione limacina from Kongsfjorden, Svalbard, were investigated with respect to ontogenetic development and life-cycle. Polytrochous larvae, which were dominant in spring (April, May), composed the lipid-richest specimens of the population, with total lipid of about 50% of dry mass (%DM). Major lipid classes were triacylglycerols (TAG) and 1-O-alkyldiacylglycerol ethers (DAGE), accounting on average for 53.1 and 21.9% of total lipid, respectively. Until summer, larvae grew to adults by utilising their storage lipids. In July/August, lipids were depleted to about 10%DM due to maturation and reproduction. Almost all animals in autumn (September) were mature and able to replenish their lipid deposits by accumulating DAGE (26.7%) and TAG (39.6%). This is probably the prerequisite for successful overwintering.Principal component analysis (PCA), based on the fatty acid compositions, revealed ontogenetic differences between polytrochous larvae, and small and full-grown adults. Higher proportions of 18:4(n-3) and 14:0 were found in polytrochous larvae and smaller adults during spring. Both fatty acids were highly significantly correlated with the proportions of TAG, which were used for growth and development because they are presumably easier to metabolise. PCA also divided C. limacina specimens into DAGE-rich and DAGE-poor. We suggest that DAGE are a long-term energy store and hypothesise that they are necessary during periods of food scarcity, but may also serve as an energy source for reproduction. The fatty acids 17:1(n-8), 15:0, 16:1(n-7) and 18:1(n-7) were significantly correlated with the proportion of DAGE but not with TAG. These fatty acids, which do not originate from their only prey, Limacina helicina, are synthesised de novo. Their abundance reflects an efficient lipid production by C. limacina. Based on the results of lipid biosynthesis and accumulation in combination with the population structure, we suggest that C. limacina has at least a 2-year life-cycle in Svalbard waters.Communicated by M. Kühl, Helsingør 相似文献
795.
796.
Ecobalance represents the basic principle for an environmental analysis and the starting point for the possibility of achieving improvements. Using the criteria related to both technology and ecology, this method has been expanded upon by IKP/PE and, over the course of many years, has proven to be a satisfactory method for those fields associated with industry and research. Data banks and software systems have been designed and are today applied in industry. An expansion of the holistic balancing to include the ‘social’ dimension is currently being developed by the IKP. Today, ecological decisions in technically and economically-associated areas are continuously being developed which place more emphasis on the preliminary developments than on a purely retrospective analysis. Aside from the continuous, further developments of these types of analysis with regard to never technical questions as well as the integration of newer aspects of optimization based on life cycle information (e.g. production balancing), the goal of further work includes the preparation of process-chain information in the respective in preliminary developments related to the design. The automobile industry consequently plays a significant role here, as was also the case in the initial transformation of methodology which was carried out in the 1990s. Finally, these developments are additionally motivated through the new ordinances presented to be employed throughout the entire EU. The responsibility attributed to a product over the course of its entire lifetime therefore plays a more prominent role. This is also reflected in ordinances like those related to the redemption of old automobiles or in the WEEE of the electronics industry (Directive on Waste Electrical and Electronic Equipment). 相似文献
797.
798.
799.
Goal and Scope
Which impact does the use of non-energetic abiotic resources (ores, minerals, etc.) have in life cycles of energy systems based on biogenic and fossil fuels? Is this kind of resource use less or more environmentally harmful than the utilisation of energetic abiotic resources (mineral oil, natural gas, etc.) in the same life cycles? This paper aims at answering these questions. In Part 1, a methodology is presented and applied to the life cycles of selected energy systems. Part 2 presents and discusses the results.Methods
The applied methodology has been explained in the Part 1. For the assessment of energetic abiotic resource use, a widely recognised method is used. For the assessment of nonenergetic abiotic resource use, no overall recognised methodological approach exists. That is why for this aspect two different methods are exemplarily applied and compared with each other.Results and Conclusion
Results show that the two assessment approaches for non-energetic resource utilisation lead to qualitatively equal results. Nevertheless they differ considerably from each other in their absolute values. This makes obvious that there is still a need for further methodological research work on that issue. Nevertheless, both methodologies yield that the accumulated effect of ore and mineral use is considerably lower than the accumulated effect of fossil primary energy utilisation in all life cycles analysed. With the assumptions made, the use of non-energetic abiotic resources only plays a comparatively subordinate role in the environmental life cycle assessment of energy systems based on biogenic and fossil fuels.Recommendation and Perspective
Results suggest that an important resource-related impact of biomass and fossil fuel powered energy systems is caused by their consumption of fossil primary energy resources. The impact of non-energetic resource use can be neglected in comparison to that. At the same time, results also make clear that there is still a considerable need for further methodical research aiming at a standardised assessment methodology for the use of non-energetic abiotic resources. 相似文献800.
Martin R. Billingham Tiago Simões Thorsten B. H. Reusch Ester A. Serrão 《Marine Biology》2007,152(4):793-801
The spatial distribution of genetic variability depends on the spatial patterns of clonal and sexual reproduction, gene flow,
genetic drift and natural selection. Species with restricted dispersal may exhibit genetic structuring within populations
with immediate neighbours being close relatives, and may show differentiation among populations. Genetic structuring of a
species may have important genetic, evolutionary and ecological consequences including distance-dependent mating success.
In this study we used microsatellite markers to show that clones of Zostera marina in a population in the Ria Formosa, Portugal, were aggregated and covered distances of up to 3–4 m. Clones within 4 m of
each other exhibited significant and positive coancestry values, reflecting the limited seed dispersal of this species. Hand-pollinations
between near (0–10.9 m), intermediate (11–32 m) and far (15 km) individuals resulted in similar levels of seed set, although
the near pollinations had higher, although not statistically significant, levels of seed abortion during maturation. Seeds
from intermediate-distance pollinations had a significantly higher proportion of seeds germinate and shorter germination time
than both the near and far seeds. Similarly, the average number of seedlings produced per pollination, used as an overall
estimate of fitness, was significantly greater for the intermediate distance when compared to both near and far pollinations.
These results suggest that the genetic structuring observed may result in both inbreeding and outbreeding depression, which
gives rise to an intermediate optimal outcrossing distance. 相似文献