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781.
782.
Marlies H?rdtlein Martin Kaltschmitt und Iris Lewandowski 《Umweltwissenschaften und Schadstoff-Forschung》1998,10(3):135-140
Zusammenfassung Teil I gibt einen überblick über den Ursprung und die Entwicklung des Begriffes “Nachhaltigkeit” im allgemeinen und für die
Landwirtschaft im speziellen. Demnach wird Nachhaltigkeit zwar unter ?kologischen, sozialen und ?konomischen Aspekten diskutiert;
eine allgemein anerkannte Definition des Begriffes existiert bisher jedoch weder für die jeweiligen Einzelaspekte noch unter
Zusammenführung aller drei Aspekte. Dies erschwert die Ermittlung und Umsetzung der Nachhaltigkeit in der Praxis.
Ausgehend von der Begriffsentwicklung und den wesentlichen heute definierten Begriffsinhalten wird deshalb für eine nachhaltige
Pflanzenproduktion aus prim?r ?kologischer Sicht eine Definition vorgeschlagen. Sie dient als Grundlage für einen methodischen
Ansatz, der eine Operationalisierung und damit eine Umsetzung der Nachhaltigkeit der Pflanzenproduktion in der Praxis erm?glichen
soll (?Teil II).
相似文献
783.
Walter Kl?pffer Peter Baccini und Martin Hess 《Umweltwissenschaften und Schadstoff-Forschung》1997,9(6):385
Ohne Zusammenfassung
Siehe auch S. 407–408 相似文献
784.
Andrea M. Hofmaier Siegfried M. G. Schwirzer Friedrich J. Wiebel Karl-Werner Schramm Martin Wegenke und Antonius A. F. Kettrup 《Umweltwissenschaften und Schadstoff-Forschung》1999,11(1):2-8
Zusammenfassung Polychlorierte aromatische Kohlenwasserstoffe (PHAK), z.B. 2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD), weisen eine Vielzahl von toxischen Wirkungen und biologischen Effekten auf. Die Substanzklasse der PHAK besitzt
die Eigenschaft der Bindung an ein cytosolisches Rezeptor-Protein, gefolgt von der Synthese bestimmter Genprodukte, u.a. von
Cytochrom P450 1A1 (CYP 1A1). In dieser Arbeit wird ein Bioassay beschrieben, der erlaubt, die Induktion von CYP 1A1 als Summenparameter
für die biologische Wirksamkeit der kritischen, halogenierten Verbindungen in komplexen Umweltmatrizes zu bestimmen. Zur Abtrennung
von Substanzen aus den Extrakten von Umweltproben (z. B. Naturstoffe und polyzyklische aromatische Kohlenwasserstoffe), die
den Bioassay st?ren k?nnen, wurde ein Ein-S?ulen-Clean-up entwickelt. Die biologisch ermittelten TEQ-Werte stimmen gut mit
den Resultaten der chemischen Analytik überein. Der Bioassay in Kombination mit dem Clean-up bietet eine zeitsparende und
kostengünstige M?glichkeit zur Untersuchung von Umweltproben.
相似文献
785.
Jürgen Schnelle-Kreis Martin Sklorz Anette Peters Josef Cyrys Ralf Zimmermann 《Atmospheric environment (Oxford, England : 1994)》2005,39(40):7702-7714
PM2.5 Particle-associated semi-volatile organic compounds (SVOC) were determined in the city of Augsburg, Germany. Daily samples were collected at a central monitoring station from late summer to late autumn 2002. The concentrations of polycyclic aromatic hydrocarbons (PAH), oxidized PAH (O-PAH), n-alkanes, hopanes and long chain linear alkylbenzenes were determined by direct thermal desorption-gas chromatography-time of flight mass spectrometry (DTD-GC-TOFMS). Additionally, PM2.5 particle mass and number concentrations were measured. The sampling campaign can be divided into two parts, distinguished by a lower temperature level in the second part of the campaign. The particulate mass concentration showed no significant changes, whereas most of the SVOC had significant higher mean and peak concentrations in the colder period. The analysis of the data showed an increased influence of non-traffic sources in the colder period, reflected by a weak shift in the PAH profile and a significant shift in the hopane pattern. Statistical analysis of the inter-group correlations was carried out. Eight clusters partly representing different sources of the aerosol have been identified. 相似文献
786.
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
787.
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
788.
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.
789.
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
790.