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1.
The reduction of pollution in the river Elbe since 1990 has resulted in changes in the processes taking place in the river. The heterotrophic degradation which dominated until 1990 was accompanied by a lack of oxygen, floating masses of sewage fungi, and sludge formation in the areas of still water. Since the early 1990s, autotrophic processes have come to dominate, with an increase in pH fluctuations and the oxygen production potential, but evidently not the chlorophyll level during the growing season. The degradable organic pollution of the Elbe is determined by algae production. The high levels of ammonium previously encountered in the Elbe were attributable to not only dischargers but also in particular the lack of oxygen in the water. Via heterotrophic nitrate assimilation, nitrate served as an oxygen reserve, resulting in high levels of nitrite. At present, when the oxygen contents are sufficient, the concentration reductions of nitrate and nitrite along the reach of the Elbe are approximately parallel, which in view of the lack of ammonium indicates the denitrification of microzones low in oxygen. The relative proportion of structurally bound substance turnover will become increasingly important for the Elbeπs material budget. 相似文献
2.
Time series of weekly water‐quality data at Schnackenburg on the Elbe River (1985—2000) were subjected to principal component analysis (PCA). Considering the amplitudes of composite patterns of variables is a step towards a process‐oriented interpretation of waterquality data. One specific objective was to investigate the impact of improved water quality after the German reunification in 1990 on primary production and the oxygen budget. To discriminate anthropogenic signals from natural fluctuations a separation of the impact of discharge was attempted based on a linear regression approach. A dominant pattern of co‐variation in the residual data could be attributed to biological activity (primary production). The most relevant variables of this 'biomode' are oxygen saturation, pH, and orthophosphate. We conclude that multivariate statistical analysis of water‐quality data can help to estimate primary production when direct observations of algal concentrations are missing. In the years from 1998—2000 the trend of the ‘biomode’ indicates an increased load of oxygen consuming biomass caused by enhanced primary production in the middle stretches of the Elbe River which corresponds with the observation of more severe oxygen deficits in the tidal section of the river. 相似文献
3.
From 1998 to 2002 investigations were carried out to estimate both the quantity and quality (heavy metal contents) of suspended matter loads discharged into a floodplain area measuring approx. 5 km2 of the Central German river Weiße Elster, a tributary of the river Saale in the Elbe river basin. Flood sediments, suspended particulate matter, and floodplain soils were investigated especially for the main pollutants Cd, Zn, Cu, Pb, Cr, and Hg. Supplementary gamma spectroscopy examinations were performed to help to identify the age of deposits in order to estimate sedimentation rates for last decades. The recent flood sediments are contaminated by up to 33 times the geogenic background (Cd). Up to 55% of the total annual SPM load of the river Weiße Elster is relocated into the investigated retention area in the flood‐stricken year 2002. The sedimentation rates for the last 50 years vary between 0.5 mm/a and 1 mm/a in far away and rarely flooded parts and between 1 mm/a and 2 mm/a in the frequently flooded parts of the inflow of the retention area. 相似文献
4.
The main objectives of this study were to describe the seasonal standing stock dynamics of phytoplankton, bacterioplankton and heterotrophic flagellates in the highly eutrophic River Elbe (Germany), and to compare the seasonal patterns observed with other streams. Emphasis was placed on examining and assessing abiotic and biotic controlling factors influencing the structure and dynamics of the riverine plankton. All the physico-chemical and biological parameters determined were within the range or somewhat higher (in the case of phytoplankton abundance and biomass) than reported for other large streams. The underwater light conditions resulting from atypically short phytoplankton growth periods of about 6 months per year and the low phytoplankton carbon to chl a ratio of 23 were identified as a major limiting factor for phytoplankton development in the River Elbe. The seasonal distribution pattern of bacterioplankton indicated probable tight trophodynamical coupling both with phytoplankton and with heterotrophic flagellates, whereas heterotrophic flagellates showed a more trophic link with bacterial densities. Although approximately constant DOC and DON levels throughout the year sustained bacterial growth rates, during the phytoplankton growing season an increase of bacterial standing stocks was observed. Although the left-bank sampling site of the Elbe is strongly influenced by the tributaries Mulde and Saale containing higher concentrations of chloride, nitrogen nutrients, heavy metals and organic pollutants, no clear differences were observed between the two sides of the river concerning the biological parameters measured. Possible reasons and the slightly higher phytoplankton abundance and diversity at the right bank are discussed. 相似文献
5.
Tracer experiments were carried out in groyne fields (GF) of the river Elbe near Havelberg (Germany) in order to estimate the hydraulic connectivity with the river channel. The characteristic times of the five groyne fields, which were estimated from the exponentially declining tracer curves in 43 runs, ranged between 15 min and 69 min and did not correlate with the water level. Methodological investigations show that single point injection and two measurements (in the outflowing water and in the dominant region) are sufficient to provide robust in‐situ tracer curves. Using simplified mathematical simulations with connected stirred tanks, the conditions are investigated for the development of breaks in tracer curves and for the occurrence of significant errors in the estimation of intrinsic residence times. It was shown that an initial uniform dye distribution is not mandatory for the estimation during steady states. In special cases, point injections are more advisable. Moreover, the mean hydraulic residence time was found to be not equivalent to the estimated characteristic time. In fact, it is mostly overestimated by tracer experiments. The degree of overestimation depends on mixing and the volumetric proportions between the different parts of the GF and can be calculated from measured dye concentration differences. For example, an overestimation of 32% was calculated for a groyne field with a commonly found circulation flow pattern. 相似文献
6.
An assessment of water quality measurements during a long‐lasting low water period in the Elbe River is presented. Weekly samples were taken from May to December 2003 at a sampling site in the middle part of the Elbe River. For multivariate data analysis, 34 parameters of 46 samplings were considered. As a result of this analysis, 78% of the variance of the data set is explained by five factors. They can be assigned to the following latent variables: season (37.5%) > tributaries (12.7%) > re‐suspension (10.4%) > discharge (9.4%) > complexation (8.5%). For the investigated sampling site, two key processes were identified as dominating factors on the water quality during low water conditions. First, seasonal phytoplankton development caused changes in redox conditions with consequences for re‐solution of pollutants from sediments. Second, tributaries have a higher impact on the main stream, due to changes in mixing processes. Therefore, in addition to flood investigations, monitoring strategies, and management plans should be developed in order to survey changes in water quality during low water conditions. 相似文献
7.
Measurements of suspended particulate matter concentration and turbidity point towards the possibility of a site‐specific algorithm (SPM), relating SPM to nephelometric turbidity units (NTU). In this paper regression models are presented that account for changes in the relationship of SPM and NTU as a result of changes in particle properties. The models have been developed by the use of daily measurements of SPM concentration and a continuous record of turbidity for the period from June 1996 to February 2001 in the River Elbe, a major river in the eastern part of Germany. The effect of changes in the particle properties with increasing water discharge was taken into account by varying the slope of a linear regression equation according to a logistic function. Water discharge, Q, was defined to be the only variable of this function—as an adequate substitute of the parameter bottom shear stress, which cannot be measured directly. Measurements of flow velocity in the River Elbe show that bottom shear stress is related almost linearly to water discharge up to bankful discharges. Regression models with slopes varying continuously with hydraulic parameters may account for the effects resulting from changes of particle characteristics and thus may have some advantages compared with models with a constant slope or models calibrated for different seasons. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
8.
An ultrafiltration methodology and the results of its application on Elbe river water are presented. Compared with other methods, Ultrafiltration allows fractionation of the molecular-weight fractions of DOC for higher volumes of solution in a shorter time. To characterize the molecular-weight fractions, the sum parameter DOC (β(DOC)) and the absorption coefficient at 254 nm a254 were measured, together with determination of a254/ β(DOC) for further characterization of the DOC fractions and to provide information about changes in parts of the UV-active substances of the total dissolved organic material. In the period May 1992 to November 1994, the DOC molecular-weight composition of 65 samples of Elbe river water were determined. At two sampling locations (Torgau-East and Meissen), the DOC content β(DOC) was approximately 6 mg/L. The high-molecular weight fraction (> 10000 g/mol) gave a mean of 13% of the total DOC content β0(DOC). The measurements showed that the molecular composition of DOC in the Elbe does not greatly differ. There was also no clear seasonal influence on the molecular-weight composition of the DOC content. During the period of investigation, the percentage part of β(DOC) and a254/β(DOC) of the high-molecular weight fraction of the total dissolved organic material increased, while the a254/β(DOC) values of the middle molecular-weight fraction remained fairly constant. The dependence of β(DOC) on discharge of the Elbe river is low. Changes in molecularweight composition of DOC were only observed during the steepest increase in river discharge during a flood event, with another spectrum of substances responsible for the increase in β(DOC) when compared with the β(DOC) for low or middle water level. 相似文献
9.
Diffuse pollution is a significant and sometimes even major component of surface water pollution. Diffuse inputs of pollutants to the surface water are related to runoff of precipitation. This means that the analysis of diffuse pollutant fluxes from the land surface to the surface water requires an analysis of water fluxes. In this paper we have modelled the average long‐term total runoff, groundwater recharge index and groundwater residence times for two large European river basins (Rhine and Elbe). We applied and compared two independently developed and recently published methods. We found that with the available large‐scale databases and methods we could simulate successfully the regional patterns of the average long‐term total runoff. The reported groundwater recharge indices and groundwater residence times should be interpreted as estimates based on available knowledge and databases. They do not represent absolute values, but illustrate the possible travel times and spatial patterns of the different runoff components that have to be taken into account for the analysis of diffuse pollution at large regional and temporal scales. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
10.
M. J. M. de Wit 《水文研究》2001,15(5):743-759
Human activity has resulted in increased nutrient levels in rivers and coastal seas all over Europe. Models that can describe nutrient fluxes from pollution sources to river outlets may help policy makers to select the most effective source control measures to achieve a reduction of nutrient levels in rivers and coastal seas. Part I of this paper describes the development of such a model: PolFlow. PolFlow was specially designed for operation at the river basin scale and is here applied to model 5‐year average nitrogen and phosphorus fluxes in two European river basins (Rhine and Elbe) covering the period 1970–1995. Part II reports an error analysis and model evaluation, and compares PolFlow to simpler alternative models. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
11.
Pollutant transport and management in the Rhine and Elbe basins is still of international concern, since certain target levels set by the international committees for protection of both rivers have not been reached. The analysis of the chain of emissions of point and diffuse sources to river loads will provide policy makers with a tool for effective management of river basins. The analysis of large river basins such as the Elbe and Rhine requires information on the spatial and temporal characteristics of both emissions and physical information of the entire river basin. In this paper, an analysis has been made of heavy metal emissions from various point and diffuse sources in the Rhine and Elbe drainage areas. Different point and diffuse pathways are considered in the model, such as inputs from industry, wastewater treatment plants, urban areas, erosion, groundwater, atmospheric deposition, tile drainage, and runoff. In most cases the measured heavy metal loads at monitoring stations are lower than the sum of the heavy metal emissions. This behaviour in large river systems can largely be explained by retention processes (e.g. sedimentation) and is dependent on the specific runoff of a catchment. Independent of the method used to estimate emissions, the source apportionment analysis of observed loads was used to determine the share of point and diffuse sources in the heavy metal load at a monitoring station by establishing a discharge dependency. The results from both the emission analysis and the source apportionment analysis of observed loads were compared and gave similar results. Between 51% (for Hg) and 74% (for Pb) of the total transport in the Elbe basin is supplied by inputs from diffuse sources. In the Rhine basin diffuse source inputs dominate the total transport and deliver more than 70% of the total transport. The diffuse hydrological pathways with the highest share are erosion and urban areas. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
12.
From March 1989 until May 1995 overall 675 hauls were performed using a commercial stow net vessel to get information concerning spatial and seasonal distribution, length frequency distribution, stock situation and migration patterns of lampreys in the Elbe estuary in northern Germany.2217 river lampreys (Lampetra fluviatilis) and 10 sea lampreys (Petromyzon marinus) were caught during the whole study period. The river lamprey occurred in 40.3% of the performed stow net hauls. The catch success was highest in the western main channel, whereas the frequency of occurrence of river lampreys was only about 10.9% at the most upstream site in the southern marginal area. In 1989 and 1990 significantly more than 50% of the hauls contained river lampreys. In contrast, from 1991 to 1995 their frequency of occurrence was lower than 40%, in 1991 even lower than 20%. Sea lampreys occurred only at 6 from 9 sampled sites and were only observed in 1990 and 1992-1994.Total lengths of river lampreys varied between 7 and 46 cm. Based on the length frequency distribution, the following three size classes of river lampreys were separated: LF I (7 to 16 cm), LF II (17-26 cm) and LF III (27-46 cm). The majority of the caught individuals could be grouped in size class LF III. Total lengths of sea lampreys ranged between 69 and 85 cm and were restricted to only one size class (PM III).70% of all sea lampreys were caught in April and May. Most of the sea lampreys were observed in the eastern main channel. The maximum average abundance of river lampreys was observed with 6.75 Ind · m−3 · 10−6 in the same area in 1992. However, in 1993 and 1994 the highest average abundances of river lampreys occurred in the western main channel.Based on redundance analysis, a significant correlation between the abundances of lampreys and the environmental variables autumn, spring, summer, salinity, water temperature, grain size, new moon and first moon quarter was found. The downstream migrating river lampreys of size class LF I und the sea lampreys during their anadromous spawning migration showed highest abundances mainly in spring, whereas high abundances of river lampreys of size class LF II in the feeding phase occurred in summer. The presence of both size classes LF I and LF II confirms the successful reproduction of river lampreys in the catchment area of the Elbe. The observation of river lampreys of size class LF III during their anadromous spawning migration was closely correlated with the variable autumn. A spring spawning migration of river lampreys was not observed. 相似文献
13.
From 1989 to 1992, the concentration of formaldehyde was measured along the Elbe estuary as well as at anchor stations. In mesocosm experiments, the turnover of formaldehyde could be investigated avoiding the variability caused by tidal advection of different water bodies. Formaldehyde concentrations in the Elbe estuary ranged from 0.5… 180 μg/L. As sources, a release by algae and microbial processes were identified. Three areas with different dominance of formaldehyde turnover processes were found in the estuary. In the limnic part of the estuary, a release of formaldehyde by algae was dominant. In the mixohaline zone and the turbidity maximum, bacterial degradation of organic matter increased the formaldehyde concentration. In the mouth of the estuary, the adjacent Wadden sea areas influenced the concentration due to formaldehyde-rich runoff from the tidal mud flats. In the other parts of the estuary, a fast degradation of formaldehyde kept the formaldehyde concentration at a low level. In sediment cores from the Elbe and a mesocosm, the formaldehyde concentrations were in the same range as in the water column. Mesocosms with and without sediment showed no significant differences in concentration levels which were similar to those measured in the Elbe at the same time. During the investigated period, no anthropogenic impacts of formaldehyde into the Elbe estuary could be detected. 相似文献
14.
In most of Europe, an increase in average annual surface temperature of 0·8 °C is observed, and a further increase is projected. Precipitation tends to increase in northern Europe and decrease in southern Europe, with variable trends in central Europe. The climate scenarios for Germany suggest an increase in precipitation in western Germany and a decrease in eastern Germany, and a shift of precipitation from summer to winter. When investigating the effects of climate change, impacts on water resources are among the main concerns. In this study, the first German‐wide impact assessment of water fluxes dynamics under climate change is presented in a spatially and temporally distributed manner using the state‐of‐the‐art regional climate model, Statistical Regional (STAR) model and the semi‐distributed process‐based eco‐hydrological model, soil and water integrated model (SWIM). All large river basins in Germany (lower Rhine, upper Danube, Elbe, Weser and Ems) are included. A special focus of the study was on data availability, homogeneity of data sets, related uncertainty propagation in the model results and scenario‐related uncertainty. After the model calibration and validation (efficiency from 0·6 to 0·9 in 80% of cases) the water flow components were simulated at the hydrotope level, and the spatial distributions were compared with those in the Hydrological Atlas of Germany. The actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions. The results for the second scenario period 2051–2060 show that water discharge in all six rivers would be 8–30% lower in summer and autumn compared with the reference period, and the strongest decline is expected for the Saale, Danube and Neckar. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). However, the uncertainty of impacts, especially in winter and for high water flows, remains high. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
16.
A method for the determination of di- and tetrachlorinated ethers (haloethers) in aqueous samples using solid-phase microextraction (SPME) combined with capillary GC has been developed. Using 100-μm polydimethylsiloxane fibers, the influence of several parameters on the SPME procedure like the exposure time of the fiber in the aqueous sample, the desorption temperature, and the salt content of the sample have been studied. Salt addition has a strong effect on the extraction efficiency of the haloethers investigated. Working with saturated salt solutions, the factor increase of the peak areas was in the range from 5 to 12. These improvements are accompanied by decreased precision and increased equilibration times. The SPME method combined with several detectors (FID, ECD, MS in SIM mode) was evaluated with respect to detection limits, linearities, and precisions. Working with salt addition and FID, detection limits of all compounds investigated were in the range of 0.3 to 1.2 μg/L. Using ECD, the LOD values (limits of detection) were only improved for the tetrachlorinated bis(propyl) ethers (<10 ng/L). Employing mass-spectrometric detection in SIM mode for all chlorinated ethers, detection limits lower than 100 ng/L could be reached. Working with saturated salt solutions, the coefficients of variation were <9% RSD. However, without salt addition, the precision is better than 2.5% RSD for all analytes. Investigations showed that the analysis of the haloethers with SPME is not influenced significantly by the matrix Elbe water. The results of two series of samples demonstrate that SPME-GC-MS allows the sensitive determination of the di- and tetrahalogenated ethers in Elbe river water. 相似文献
17.
An assessment of water quality measurements during a spring flood in the Elbe River is presented. Daily samples were taken at a site in the middle Elbe, which is part of the network of the International Commission for the Protection of the Elbe River (IKSE/MKOL). Cluster analysis (CA), principal components analysis (PCA), and source apportionment (APCS apportioning) were used to assess the flood‐dependent matter transport. As a result, three main components could be extracted as important to the matter transport in the Elbe River basin during flood events: (i) re‐suspended contaminated sediments, which led to temporarily increased concentrations of suspended matter and of most of the investigated heavy metals; (ii) water discharge related concentrations of pedogenic dissolved organic matter (DOM) as well as preliminary diluted concentrations of uranium and chloride, parameters with stable pollution background in the river basin; and (iii) abandoned mines, i.e., their dewatering systems, with particular influence on nickel, manganese, and zinc concentrations. 相似文献
18.
Ren Schwartz 《洁净——土壤、空气、水》2006,34(3):223-233
Because of the significant reduction of flow velocity relative to the main current there is an accumulation of sediment material in the centre of the groyne fields over time (years to decades) up to a maximum of 1.5 m. Based on the element‐ and compound‐specific depth functions of this fine‐grained material with high organic matter content the sedimentation history of the Elbe River sediments concerning the environmentally relevant nutrients and pollutants can be reconstructed. It could be shown that the fresh sediments are less polluted than the deeper older ones. During the extreme flood of the river Elbe in August 2002 the critical erosion shear stress in the groyne fields was high enough to remobilise a considerable portion of the sediment depot. The hazard to the environment is high due to the fact that a significant part of the remobilised polluted sediments was distributed over the recent floodplain which is normally used as pasture. Thus these groyne field sediments represent a temporary danger for the water quality of the river Elbe. But the hazard of the solids sedimented in the recent floodplain of the river can be viewed as long‐lasting. 相似文献
19.
Long‐term variations and temporal scaling of hydroclimatic time series with focus on the German part of the Elbe River Basin 
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下载免费PDF全文 Long‐term variations and temporal scaling of mean monthly time series of river flow, precipitation, temperature, relative humidity, air pressure, duration of bright sunshine, degree of cloud cover, short wave radiation, wind speed and potential evaporation within or in vicinity of the German part of the Elbe River Basin are analyzed. Statistically significant correlations between the 2–15 year scale‐averaged wavelet spectra of the hydroclimatic variables and the North Atlantic Oscillation‐ and Arctic Oscillation index are found which suggests that such long‐term patterns in hydroclimatic time series are externally forced. The Hurst parameter estimates (H) based on the Detrended Fluctuation Analysis (DFA) indicate persistence for discharge, precipitation, wind speed, air pressure and the degree of cloud cover, all having an annual cycle and a broad low‐frequency distribution. Also, DFA H parameter estimates are higher for discharge than for precipitation. The major long‐term quasi‐periodic variability modes of precipitation detected using Singular Spectrum Analysis coincide with those detected in the discharge time series. Upon subtraction of these low‐frequency quasi‐periodic modes, the DFA H parameter estimates suggest absence of the persistence for both precipitation and discharge. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
20.
This paper reports changes in dissolved organic carbon concentration β(DOC) and the relation between UV-active and non-UV-active components determined for Elbe river water and river bank infiltrate in the Torgau river basin between 1992 and 1994. Using an ultrafiltration method, the fractionation of the DOC content was obtained for the fractions > 10 000 g/mol, 1 000…10 000 g/mol, and < 1 000 g/mol. The spectral absorption coefficient at 254 nm a254 of the molecular-weight fractions was also measured. The mean total DOC concentration of Elbe river water decreased from 6.0 mg/L to below 3.9 mg/L along two investigated flowpaths. Two thirds of the decrease occurred within the first few metres of the river bed and one third along the 350 m length of the groundwater flowpaths. The a254 values showed a significant decrease from 14.8 1/m in Elbe river water to 7.8 1/m in the aquifer. Along a flowpath, the proportion of low-molecular weight fraction of DOC increased, the proportion of high-molecular weight fraction decreased, and the proportion of the 1 000…10 000 g/mol molecular-weight fraction remained relatively stable. The Elbe river water contained the main portion of UV-active compounds in the fraction 1 000…10 000 g/mol, and this was also the case for samples of river infiltrate. For the high-molecular weight fraction, mainly non-UV-active compounds were attenuated in the river bed sediment. 相似文献