Management von schadstoffbelasteten Feinsedimenten in Bundeswasserstraßen

The Federal Institute of Hydrology has developed operating strategies in order to deal with dredged material within the scope of the Waterways and Shipping Administration. Sediments will be assessed based on certain quality parameters. The potential environmental impact at the source and relocation areas has to be evaluated in respect to ecological and economical issues. A coordinated sediment management plan for the Rhine River was commissioned. The most important contaminated sedimentation areas were identified, and special sedimentation areas were classified based on ecological impact or even risk. Proposals for economical and ecological strategies are discussed. Further developments for operational instructions dealing with sediments and dredged material in federal waterways are still being processed. The objectives of the river basin commissions as well as those of the stakeholders have to be met in an appropriate manner. In the framework of the analysis and impact of climate change on both sediment quantity and quality for optimizing sediment management, one or more dimensional hydraulic models will be applied. This will help gain a better insight into the understanding of contaminant transport in freshwater bodies.     

Insektizide in Fließgewässern

In streams with an agricultural source of catchment, insecticide contamination and hydrodynamic stress increased with the rate of surface runoff. In this investigation, surface runoff was responsible for an insecticide contamination of the water of up to 6 μg/lParathion and of suspended particles of up to 302 μg/kgFenvalerate. Surface runoff also induced an increase of discharge up to one order of magnitude over one day. As a consequence, the number of macroinvertebrate species was discreased by 73% and the species composition was modified. Laboratory and field investigations pointed out that insecticide contamination is the most relevant cause of these observed biological changes. This work describes the population dynamics of a sensitive species and, in addition, the strategies of survival of a tolerant species.     

Pharmazeutisch aktive Substanzen in kleinen Fließgewässern

Background

Current hydrological research is increasingly focusing on pharmaceutically active compounds (PhACs). Concerning the issue of quality of drinking water, this problem has also become the focus of public interest. However, in spire of the fact that the fate of chemicals in surface waters has been assessed in great detail, the influence of groundwater-exchange is yet only little known.

Goal

This study gives emphasis to the question of how transport and degradation of PhACs interact with the exchange of surface water with groundwater. Special interest is given to alternating groundwater regimes.

Methods

Based on a small stream system in the north of Berlin, Germany, a one-dimensional compartment-model was established using differential mass-balance. The stream which, at its mouth, discharges 0.3 m³ s^?1 is already well investigated and thus provides a good empirical data basis. The processes taken into account by the model were ‘exchange of surface-water with groundwater’, ‘decomposition’ as well as ‘transport’ of PhACs. Calculations were performed using the commonly used analgesic Diclofenac as an example and defining 81 scenarios by different groundwater regimes. Hasse Diagramm Technique was used to compare the scenarios.

Results

All scenarios show a big influence of groundwater-exchange to the fate and concentration of PhACs in surface waters. In the case of the modelled stream system, dilution by groundwater was more responsible for a decrease in concentration than degradation was. Furthermore, on the background of a standard scenario, the loss due to groundwater by 5.4 percent was in the same magnitude as the loss due to decomposition (9.7 percent). A crucial difference between punctual versus linear afflux of groundwater has not been observed.

Discussion

The alteration of discharge resulted in a big influence of the case differentiation between ‘constant velocity’ and ‘constant cross-section’. Furthermore, the model was based on the assumption that groundwater was unloaded with PhACs or diluted very well in comparison to the stream. In contrast, regarding measurements in the catchment, groundwater could even be a diffuse source of the contamination of the stream.

Conclusions

The fate of PhACs in our model is crucially driven by interactions with groundwater. Therefore, assessing the risk emanating from substances like Diclofenac, it is very important to regard their accessibility to decomposition as well as the morphology of the stream-system and its interactions with the groundwater.

Perspectives

In this model, the process of transport from the surface to groundwater back to the surface was dealt with insufficiently; in order to be able to observe fully developed interaction in a further step of modelling, a groundwater-transportmodel should be coupled completely with a surface-water-model.     

Analyse „stetigkeitsbasierter“ Methoden zur Bestimmung von Stofffrachten in Fließgewässern

Aim and background

Increasing ecological awareness puts the load as a tool for water quality assessment in the foreground. Therefore it is very desirable to find optimal procedures for any given situation on basis of existing data. Criteria will be derived to fill that desire.

Method

The load for a water ingredient is an integrated entity of time-continuous loads (product of concentration and flow) for a given time, i.?e. a year (yearly load). Normally you can only observe a sample (in a statistical meaning) of these data. Therefore, load calculations vary with the concrete sample given. Each such calculation represents an estimation of the load, afflicted with some uncertainty. This uncertainty can be quantified, at least approximatively, by adding variance (scatter around “expected” mean) and the square of bias (divergence of “expected” mean from true mean). This quantity is called “mean squared error”. The methodological results will be illustrated by examples.

Focus

The main focus lies on the methodologies, which, besides data of concentrations observed discretely in time, additionally use quasi-continuously recorded data of other variates, namely the flow. For that situation, statistical models are developed and the load derived and estimated according to existing data. Hereby it is seen that all model based estimation formulae can be described as standard sampling formulae plus some additional terms which stem from comparison of some measurements (i.?e. mean) for quasi-continuous and discrete samples. This way a “continuity-correction” is performed on the standard formulae for the sampling case. This method is called “continuity-based” load determination.

Results

A surprising result is that no complicated mathematical-statistical models are necessary to determine the load. A simple linear concentration- or load-flow-model is sufficient. Additional variates lead, most of the time, to a larger mean squared error in load estimation, even when it is well known that they cannot detoriate the model fit. Only models which describe the concentration extraordinarily precise, near perfection, result in a smaller error.

Implications

It is enough to use one of the given formulae with some “continuity correction” to calculate a load. That can be done without using any software.     

Stabilitätsverhalten von ausgewählten anorganischen Spurenstoffen in Niederschlagsproben

The stability of H⁺, NH ₄ ⁺ , and PO ₄ ^3? ions in rainwater samples was in vestigated under different conditions cf storage and transport. Microbiological and physicochemical processes account for changes. Suppression of microbiological activities in deposition networks using conventional analyses may be achieved by adding AgCl-powder and by cooling to +4 °C.     

Chemodynamische Verteilung lipophiler organischer Schadstoffe in Gewässern

Using a simple chemodynamical model, the distribution of lipophilic organic contaminants between the solid (suspended particulate matter, sediment) and the aquatic phase in waters has been studied. For numerous organic contaminants found in the river Elbe, the partitioning between the solid and aquous phases has been calculated.     

Abschätzung des Beitrages kommunaler Kläranlagen an Schadstoffkonzentrationen in Oberflächengewässern

A number of products, such as washing agents or pharmaceuticals, enter the hydrosphere mainly with municipal wastewater. In this case the predicted environmental concentrations (PEC) of substances are largely determined by their elimination in municipal wastewater treatment plants and by the dilution ratio of wastewater in the rivers. In this article some rough estimates of the wastewater ratio in German rivers are presented and as a starting point for a more complex model for calculating the PEC more exactly, data on the fluctuation of river flow rates are shown.     

Die rolle der umweltprobenbank in der Umweltüberwachung am beispiel von chlorierten kohlenwasserstoffen in ausgewählten matrizes

For precautinary environmental protection the Environmental Specimen Bank (ESB) has been successfully established as a permanent environmental surveillance tool in Germany. The presented monitoring results on chlorinated hydrocarbons (CHC) show very clearly the effects of political decisions and can be used for the identification of pollutant sources. The CHC burden of breams (Abramis brama) from five German rivers (Elbe, Rhein, Saar, Mulde, Saale) gives an current overview of the pollution situation of different limnic ecosystems in Germany. A calculation model about the distribution of organic pollutants between different tissues offers the possibility to predict concentrations in liver and muscle of breams. Legislative emission restrictions have led to a significant decrease of dioxin levels in herring gull (Larus argentatus) eggs between 1988–1996.     

Großräumige Regionalisierung der Kohlenstoffbindung in Wäldern Nordrhein-Westfalens

Background, aim and scope The United Nations Framework Convention on Climate Change understands carbon fixation in forests as an important contribution for the reduction of atmospheric pollution in terms of greenhouse gases. According to the German forest inventory on carbon in biomass an amount of 191?t C/ha was roughly estimated, without any spatial differentiation. Therefore, the aim of this investigation was to statistically identify factors that are significant for the carbon fixation and to map the spatial patterns of C sequestration in the federal state North Rhine-Westphalia. Materials and methods Together with information on climate, elevation, vegetation, and deposition, data from two forest monitoring networks were analysed statistically. Geostatistics and the decision tree algorithms Classification and Regression Trees (CART) and Chi-Square Automatic Interaction Detection (CHAID) were applied to calculate surface maps from punctual data on C in vegetation, in dead wood and in soil. Whereas spatial autocorrelation could be detected for the C loads in the humus layers, no surface maps could be calculated for the C contents of the mineral soils and for the forest trees/dead wood. Here, CART and CHAID were used to derive decision trees that were applied on available surface data to predict C loads for the entire study area. Results About 19?t C/ha could be predicted for the humus layer, 67?t C/ha for forest trees/dead wood and 90.7?t C/ha for the soil. An overall mean of 177?t C/ha was calculated for North Rhine-Westphalia lying 14?t C/ha below the German wide mean. Discussion Compared to the calculated results in another investigation a total of 68?mio. t C for the above ground dendromass was estimated. This is 11?mio. t C/ha higher than the amount calculated in this study and may be due to the fact that this value includes the C-pools in both, the brushwood and herbaceous layer in their estimations. The average C concentration in the humus layer all over Germany was found to amount for 20.7?t C/ha which is slightly above the C storage calculated for North Rhine-Westphalia. In the same study a Germany wide C average of 87.9?t C/ha was calculated which is very close to the 90.7?t C/ha calculated in this study. Conclusions The surface estimations of the C-pools in the above-ground biomass, the humus layer and the mineral soil enable to map the efficiency of the C-bounding capacity regarding the fixation of the greenhouse gas CO₂. The mean values derived in this study are in good accordance with estimations based on other techniques. Recommendations and perspectives The approach presented should be verified by application to Germany wide inventory data and by means of Regression Kriging. Furthermore, the C-fixation under climate change should be calculated by combining statistical methods and the dynamic modelling tool WASMOD.     

Bestimmung von leicht freisetzbarem Cyanid in Böden und Wässern mit der Mikrodestillation

Easy-liberatable cyanide has to be analysed if soils and waters are contaminated by cyanide. The aim of this study was to determine easy-liberatable cyanide in these environmental samples using a micro-distillation apparatus by means of a modified digestion vessel. Pure aqueous solutions of different cyanide species, five contaminated and uncontaminated soil samples and two water samples were analysed by micro-distillation according to the German standards. Recovery was determined by analysis of spiked samples. When using the modified digestion vessels, the pH of 4 which is demanded by the standard method can be adjusted. The recovery of potassium cyanide and weakly-complexed zinc-cyanide ranged from 93–101% for standards, and from 87–98% for spiked samples. In contrast, the recovery of strong iron-cyanide complexes was below 4% both for pure solutions and spiked samples. The precision of the method expressed as a relative standard deviation was 25% in cases of very low easy-liberatable cyanide contents (< 1 mg CN kg^?1) and below 12% in case of high easy-liberatable cyanide contents (> 1 mg CN kg^?1) for contaminated soils. The determination of easily-liberatable cyanide in soils and waters using micro-distillation combined with the modified digestion sample is an alternative to other distillation methods.     

Mikrobiologische Volatilisierung von anorganischem Selen aus Deponiesickerwässern bei umweltrelevanten Konzentrationen

Background, aim, and scope Determination of the rates of microbial alkylation are of interest with respect to natural attenuation of harmful selenium concentrations or selenium charges in contaminated ecosystems. Materials and methods Landfill gas and the headspace of microbial microcosm incubation vessels were sampled in Tedlar^® bags. On-line hyphenation of an efficient enrichment method (cryotrapping-cryofocusing), a gaschromatographic separation technique, and the sensitive ICP-MS detection system was used for speciation of volatile organoselenium compounds. A detection limit at the ultra trace level (pg Se) was achieved with this CT-CF-GC-ICP-MS technique. Results Incubation of landfill leachate with Alternata alternata as an active methylating organism showed a production of volatile selenium compounds (DMSe, DMDSe, EMDSe, DEDSe) over the whole range of applied inorganic selenium concentrations (10?µg?L^–1 to 10?mg?L^–1), with volatilization rates of up to 10?mg m^–3?d^–1. For selenium concentrations of 1?mg?L^–1 in the nutrient broth, up to 7?% of the inorganic selenium was volatilized after one week. The same volatile selenium compounds were observed in landfill gas. Discussion The amount of volatilized selenium was comparable to that found in other studies with microbial pure cultures as well as isolates from waters or soils, but at much lower initial concentrations used in the incubations. Conclusions The alkylation of selenium in the enriched mixed culture from landfill leachate at environmentally relevant concentrations indicates that the organoselenium compounds of same species composition and distribution determined in landfill gas are produced by microorganisms. Recommendations and perspectives The microbial alkylation of toxic inorganic selenium species to less toxic or non-toxic, volatile compounds is an efficient method for bioremediation of contaminated sites even at relatively low Se concentrations.     

Insektizid-Auswirkungen auf Fließgewässer-Lebensgemeinschaften

Event-triggered sampling from a stream in agricultural terrain has revealed a level of contamination considerably higher than that which has generally been assumed, although only moderate amounts of insecticides had been washed away from the cultivated fields. Macroinvertebrate sampling carried out in parallel with the contamination measurements documented severe negative effects of the insecticide inputs on the aquatic community; 8 of the 11 species disappeared from the water for a period of 3 to 6 months. In field investigations, as well as inin situ bioassays,L. lunatus andG. pulex exhibited acute responses (drifting, mortality during drifting) which were seen to be significantly higher than those values noted at an uncontaminated control site as far as even 2000 m from the input site. In these bioassays, where the animals are confined in cages, the insecticide toxicity inG. pulex may be overestimated compared to the field data since the drifting behavior of this species normally helps it to avoid contamination.     

Persistente organische Schadstoffe in Böden, Gewässern und in Firn der Region nördliches Piringebirge (Bulgarien)

Systematic environmental screenings are still the exception in South-Eastern Europe. Especially, there is a decisive lack of information concerning the occurrence and behaviour of xenobiotic and toxic compounds like volatile-and non volatile halogenated organics, suppressed by the surrogate AOX, synthetic chelating agents, pesticides, like DDT as well as chlorate in the biosphere. The analysis of soils, waters and firns of a representative area in Bulgaria, the Pirin mountains, indicate a relatively low back ground pollution. The accumulation of the xenobiotics in this high mountain region is recognised to be low. Nevertheless, traces of pesticides and chelating agents like EDTA and NTA in ice (firns) and soils were found. The surrogate AOX should be a parameter, suitable for routine environmental screenings of such areas.     

Straßenversiegelung in Deutschland und ihre Beinflussung der Umwelt im Vergleich mit anderen OECD-Ländern

Since the increasing awareness of environmental damage, attention has focussed on the problems caused by the extension of car traffic. The number of cars has permanently increased over the years and is predicted to continue in the future. The number of cars registered worldwide already passed the number of 500 million in the year 1988 (OECD, 1995). Two major problems are linked to the increase in car traffic: The air pollution by engine conbustion and the so-called sealing of the ground by pavements. The streets dramatically cut into coherent areas, separate biotopes, animal and plant populations (BBR, 1998). Facts about grund sealing in Germany are presented and compared to those of other OECD-countries. Environmental consequences are discussed.     

Ein Moosbiomonitoring zur Ermittlung atmosphärischer Elementeinträge in die Euroregion Neiße (D, PL, CZ)

This article describes a biomonitoring using mosses in order to determine the amount and distribution of the atmospheric deposition of 37 elements in the European region of the Neisse river following the political and economic changes. These results are compared with the findings in other regions. Additionally, the accumulation characteristics ofPleurozium schreberi andPolytrichum formosum, the two moss species used in the study, were compared with one another. Until the beginning of the 1990s, this region was part of the socalled “black triangle”, an area characterised by extremely high atmospheric dust pollution. Through the closing of numerous factories, the equipment of power plants with filters, and the decreasing importance of brown coal as a source of household heating, the situation has changed considerably. Today, the pollution levels in the European region of the Neisse river are comparable with those in the western part of Germany. Higher levels were only determined for Fe and Ti, which can be attributed to the broader usage of brown coal as a source of energy. In the area around Katowice, Poland, the levels of certain elements were found to be more than ten times higher than in the European region of the Neisse. These highly elevated levels of atmospheric contamination in the industrial district of Upper Silesia indicate that action is urgently needed.     

Sequentielle Schwermetallextraktion aus Staubniederschlägen und Straßensedimenten

For the application of sequential extraction of heavy metals from samples that can only be obtained in amounts of a few milligrams (micro samples, e.g. airborne dust fallout), the method afterZeien &Brümmer (1989) was progressed. A down scale to 1∶100 was carried out and the accuracy of this method with variable sample amounts of about 20 mg and an extraction volume of 500 μl was proofed with standard soil samples. The influence of variable extraction ratios (ratio of sample amount and volume of extraction solvent) and the influence of intensive treatment of dust sampled by the Bergerhoff-method (VDI 2119/2, 1972) prior sequential extraction, was within the precision of measurement of our method. Thus, we showed that sequential extraction can be applied for the investigation of heavy metal mobilization in micro samples with variable sample amounts. A first application of our method for microsamples was carried out to investigate airborne dust fallout and street sediments at two urban sites where different heavy metal immission rates due to traffic influence occur. These investigations will be presented in part 2 (“Sequential extraction of heavy metals from urban dust”).     

Bewertungsmaßstäbe zur Beurteilung von Schadstoffbelastungen in Böden anhand der Bioverfügbarkeit

Until now, assessment of contaminated sites is based on variable protection goals, whereby total contents and in part mobile contents are considered. Due to interactions of pollutants in soil and bound residues, total contents do not reflect the actual risk. In contrast an investigation based on availability/bioavailability of contaminants would enable a harmonization of the protection-goal-based evaluation and a closer-to-reality risk assessment for the individual location.