Land-parcel land-use history as a key to site selection for documenting soil contamination risk: A case study from Australian Suburbia     

Yu Jie  Ursula Pietrzak  Jim Peterson 《地球空间信息科学学报》2013,16(4):257-261

In that orcharding in early-to-mid twentieth century southeastern Australia involved use of certain heavy metal and As compounds in regular pest-control spray procedures, some interest attaches to the possibility that these landparcels are underlain by’ soils with above-background Cu, Pb and As levels. Interpretation of Land-cover changes allowed land parcels previously occupied by orchards to be identified in the 1950s through time-series air-photos. A comparison of soil analysis results referring to soil samples from control sites, and from land parcels formerly occupied by orchardists, shows that contamination (above-background) levels of cations in the pesticides can be found in the top 6 cm of former orchard soils. It is clear that digital spatial data handling and culturally-informed air photo interpretation has a place in soil contamination studies, land-use planning (with particular reference to re-development) and in administration of public health.  相似文献   

A DUNITE-NORITE LUNAR MICROBRECCIA     

G. Jeffrey Taylor  Ursula B. Marvin 《Meteoritics & planetary science》1971,6(3):173-180

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A Study of Long-Term MTBE Attenuation in the Borden Aquifer, Ontario, Canada   总被引：5，自引：0，他引：5  

Mario Schirmer  James F. Barker 《Ground Water Monitoring & Remediation》1998,18(2):113-122

In 1988 and 1989, a natural gradient tracer test was performed in the shallow, aerobic and aquifer at Canadian Forces Base (CFB) Borden. A mixture of ground water containing dissolved oxygenated gasoline was injected below the water table along with chloride (Cl-) as a conservative tracer. The migration of BTEX, MTBE, and Cl was monitored in detail for 16 moths. The mass of BTEX compounds in the plume diminished significantly with time due to intrinsic aerobic biodegradation, while MTBE showed only a small decrease in mass over the 16-month period. In 1995/96, a comprehensive ground water sampling program was undertaken to define the mass of MTBE still present in the aquifer. Since the plume had migrated into an unmonitored section of the Borden Aquifer, numerical modeling and geostatistical methods were applied to define an optimal sampling grid and to improve the level of confidence in the results. A drive point profiling system was used to obtain ground water samples. Numerical modeling with no consideration of degradation pedicted maximum concentrations in excess of 3000 μg/L; field sampling found maximum concentrations of less than 200 μg/L. A mass balance for the remaining MTBE mass in the aquifer eight years after injection showed that only 3% of the original mass remained. Sorption, volatilization, a biotic degradation, and plant uptake are not considered significant attenuation processes for the field conditions. Therefore, we suggest that biodegradation may have played a major role in the attenuation of MTBE within the Borden Aquifer.  相似文献   

Hydrographische Untersuchungen im Westeuropäischen Becken im Frühjahr 1984 während NOAMP II     

Dr. Gerd Axel Becker  Ingrid Bork  Dr. Ursula Schauer 《Ocean Dynamics》1984,37(4):157-164

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Terrestrial vegetation redistribution and carbon balance under climate change   总被引：1，自引：0，他引：1  

Wolfgang Lucht  Sibyll Schaphoff  Tim Erbrecht  Ursula Heyder  Wolfgang Cramer 《Carbon balance and management》2006,1(1):6-7

Background  

Dynamic Global Vegetation Models (DGVMs) compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present) to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100.  相似文献   

Echinoids from the Belpberg Beds (Obere Meeresmolasse, Middle Burdigalian) in the area of Bern (Switzerland)   总被引：1，自引：0，他引：1  

Andreas Kroh  Ursula Menkveld-gfeller 《Eclogae Geologicae Helvetiae》2006,99(2):193-203

The present paper deals with the echinoid fauna of the Belpberg Beds, a lithostratigraphic unit in the Upper Marine Molasse cropping out southeast of Bern (Switzerland). In this unit, echinoids, in contrast to mollusks, are rare and of low diversity. The scarcity of echinoids is related to the environmental setting dominated by monotonous siliciclastic deposits and strong diagenetic alteration. The echinoid fauna consists of three species Psammechinus dubius dubius, Echinocardium deikei and Hemipatagus ocellatus? Psammechinus dubius dubius and H. ocellatus typically occur in Burdigalian sediments in the Paratethys and help to confirm the dating obtained from the microfossils and molluscs of the Belpberg Beds. Furthermore, the Belpberg echinoid fauna is especially relevant for the palaeobiogeography with species common to both the Rh?ne Basin and the Central Paratethyan faunas.

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Zusammenfassung. Die vorliegende Arbeit besch?ftigt sich mit der Echinidenfauna der Belpberg Schichten (Obere Meeresmolasse) bei Bern. Im Gegensatz zu den Mollusken sind die Echiniden selten und wenig divers. Dies kann einerseits auf das sediment?re Regime, und andererseits auf diagenetische Ursachen zurückgeführt werden. Insgesamt konnten drei Arten nachgewiesen werden (Psammechinus dubius dubius, Echinocardium deikei und Hemipatagus ocellatus?). Zwei davon treten in der Paratethys charakteristischerweise im Burdigalium auf und lassen ein ebensolches Alter für die Belpberg Schichten als wahrscheinlich erscheinen. Aus pal?obiogeographischer Sicht ist die Belpberg-Echinidenfauna von besonderem Interesse, das sie ein Bindeglied zwischen Rh?ne Becken und Zentraler Paratethys darstellt.

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Macrophytes and phytobenthos as indicators of ecological status in German lakes — a contribution to the implementation of the water framework directive     

Jochen Schaumburg  Christine Schranz  Gabriele Hofmann  Doris Stelzer  Susanne Schneider  Ursula Schmedtje 《Limnologica》2004,34(4):302-314

A new assessment system for macrophytes and phytobenthos in German lakes according to the Water Framework Directive of the European Community is described. Based on biological, chemical and hydromorphological data from about 100 lake sites covering the main ecoregions, hydromorphological lake types and degradation forms, biocoenotic types could be defined. For developing a classification system the quality element macrophytes and phytobenthos was divided into two components: macrophytes and benthic diatoms. For macrophytes 4 and for benthic diatoms 4 lake types were identified. The benthic vegetation at reference conditions is described and degradation is characterised as deviation in benthic vegetation species composition and abundance from the reference biocoenosis. For classification in five ecological status classes, several metrics were developed and used in combination with existing indices. For a few of the described lake types further investigations are necessary before a classification can be developed.  相似文献   

The Luna 20 lithic fragments,and the composition and origin of the lunar highlands     

G.Jeffrey Taylor  Michael J Drake  John A Wood  Ursula B Marvin 《Geochimica et cosmochimica acta》1973,37(4):1087-1106

Luna 20 soil 22003,1 (250–500 μ) is similar to Apollo 16 soil 61501,47 (250–500 μ) in terms of the percentage of different types of particles. However, among the lithic fragments, the Apollo 16 sample contains a greater percentage of fragments with more than 70 wt. % modal plagioclase and a significantly greater proportion of KREEP-rich particles. Modal analyses of non-mare lithic fragments in Luna 20 and Apollo 11, 14, 15 and 16 indicate that the KREEP-poor highland regions (the bulk of the lunar terrae), though relatively feldspathic, are compositionally inhomogeneous, ranging in plagioclase content from approximately 35 to 100 wt. %. The average plagioclase content lies in the range 45–70 wt.%. Luna 20 pyroxene analyses cluster in two groups, one more magnesian than the other. The groups persist when pyroxene analyses from KREEP-poor noritic, troctolitic and anorthositic lithic fragments from Apollo 11, 14, 15 and 16 and Luna 20 are included. Olivine compositions mimic these pyroxene groups.Within each pyroxene group Cr₂O₃ and TiO₂ decrease as $\text{Fe}\text{(Fe + Mg)}$ increases, suggesting a relationship by fractional crystallization. The two groups suggest that at least two magma compositions were involved. To account for these observations we envisage a Moon-wide magma system in which initial accretionary heterogeneities were imperfectly erased by diffusion and convection. During the cooling of this magma system fractional crystallization was effected by the flotation of plagioclase and sinking of pyroxene, olivine and perhaps ilmenite. The endproduct was an upper layer enriched in plagioclase and a lower layer enriched in mafic silicates. KREEP-rich rocks, which are predominantly noritic in major element composition, may be mechanical mixtures of KREEP-poor norite and material residual after fractional crystallization of the surface magma system.  相似文献   

Estimating surface runoff and groundwater recharge in an urban catchment using a water balance approach     

Weatherl  Robin K.  Henao Salgado  Maria J.  Ramgraber  Maximilian  Moeck  Christian  Schirmer  Mario 《Hydrogeology Journal》2021,29(7):2411-2428

Hydrogeology Journal - Land-use changes often have significant impact on the water cycle, including changing groundwater/surface-water interactions, modifying groundwater recharge zones, and...  相似文献   

PHT3D‐UZF: A Reactive Transport Model for Variably‐Saturated Porous Media          下载免费PDF全文

Ming Zhi Wu  Vincent E.A. Post  S. Ursula Salmon  Eric D. Morway  Henning Prommer 《Ground water》2016,54(1):23-34

A modified version of the MODFLOW/MT3DMS‐based reactive transport model PHT3D was developed to extend current reactive transport capabilities to the variably‐saturated component of the subsurface system and incorporate diffusive reactive transport of gaseous species. Referred to as PHT3D‐UZF, this code incorporates flux terms calculated by MODFLOW's unsaturated‐zone flow (UZF1) package. A volume‐averaged approach similar to the method used in UZF‐MT3DMS was adopted. The PHREEQC‐based computation of chemical processes within PHT3D‐UZF in combination with the analytical solution method of UZF1 allows for comprehensive reactive transport investigations (i.e., biogeochemical transformations) that jointly involve saturated and unsaturated zone processes. Intended for regional‐scale applications, UZF1 simulates downward‐only flux within the unsaturated zone. The model was tested by comparing simulation results with those of existing numerical models. The comparison was performed for several benchmark problems that cover a range of important hydrological and reactive transport processes. A 2D simulation scenario was defined to illustrate the geochemical evolution following dewatering in a sandy acid sulfate soil environment. Other potential applications include the simulation of biogeochemical processes in variably‐saturated systems that track the transport and fate of agricultural pollutants, nutrients, natural and xenobiotic organic compounds and micropollutants such as pharmaceuticals, as well as the evolution of isotope patterns.  相似文献