Electrical resistivity tomography as monitoring tool for unsaturated zone transport: an example of preferential transport of deicing chemicals

Non-invasive spatially resolved monitoring techniques may hold the key to observe heterogeneous flow and transport behavior of contaminants in soils. In this study, time-lapse electrical resistivity tomography (ERT) was employed during an infiltration experiment with deicing chemical in a small field lysimeter. Deicing chemicals like potassium formate, which frequently impact soils on airport sites, were infiltrated during snow melt. Chemical composition of seepage water and the electrical response was recorded over the spring period 2010. Time-lapse electrical resistivity tomographs are able to show the infiltration of the melt water loaded with ionic constituents of deicing chemicals and their degradation product hydrogen carbonate. The tomographs indicate early breakthrough behavior in parts of the profile. Groundtruthing with pore fluid conductivity and water content variations shows disagreement between expected and observed bulk conductivity. This was attributed to the different sampling volume of traditional methods and ERT due to a considerable fraction of immobile water in the soil. The results show that ERT can be used as a soil monitoring tool on airport sites if assisted by common soil monitoring techniques.     

Arbeitskreis der Landesanstalten und-Ämter: Konzeption der künftigen Aufgabenbereiche

The expert panel for biological indication and effect research of the state institutes and agencies, pursues the harmonisation and optimisation of methods used for biological indication since 1980. This demonstrated increased significance after the fall of the Berlin Wall and the admission of the new German states, formerly East Germany. The publication of recommendations and the co-operation with other panels of experts (for example the VDI (association of German engineers) build the basis for the expert panel’s effect on the public. As first federal biological indication system, the expert panel, together with the federal institute for the environment, introduced moss-monitoring in the Federal Republic of Germany. For the future, the main point of effort will still lie in the exchange of information between state agencies and the harmonisation of methods. Above this, the expert panel should control the co-ordination of biological indication for a federal environment surveillance, develop evaluation strategies and methods, point out research deficiencies and develop new methods when necessary. Thus, for example, the expert panel has to point out possible connections and co-operations towards the monitoring of genetically manipulated organisms and changes in climate. Existing biological indication methods, including moss-monitoring, are to be screened for actuality and, when necessary, are to undergo further developments. The expert panel will also work on the development of effect-related environmental indicators as tools for an indication of ecological sustainability.     

Advantages and possibilities of solid recovered fuel cocombustion in the European energy sector

The 1999/31 Elemental Carbon Directive sets strict rules on the disposal of untreated municipal solid waste in the European Union countries and forces a reduction of the biodegradable quantities disposed off to landfills up to 35% of the amount produced in 1995 in the coming decade. More environmentally friendly waste management options shall be promoted under the framework of the Community Waste Strategy ([96] 399 Final). In this context, the production and thermal use of solid recovered fuels (SRFs), derived from nonhazardous bioresidues and mixed- and mono-waste streams, could be a key element in a future waste management system. Within the scope of the European Demonstration Project, RECOFUEL, SRF cocombustion was demonstrated in two large-scale lignite-fired coal boilers at RWE power station in Weisweiler, Germany. As a consequence of the high biogenic share of the cocombusted material, this approach can be considered beneficial following European Directive 2001/77/EC on electricity from renewable energy sources (directive). During the experimental campaign, the share of SRF in the overall thermal input was adjusted to approximately 2%, resulting into a feeding rate of approximately 25 t/hr. The measurement campaign included boiler measurements in different locations, fuel and ash sampling, and its characterization. The corrosion rates were monitored by dedicated corrosion probes. The overall results showed no significant influence of SRF cocombustion on boiler operation, emissions behavior, and residues quality for the thermal shares applied. Also, no effect of the increased chlorine concentration of the recovered fuel was observed in the flue gas path after the desulfurization unit.     

Grey Box and Component Models to Forecast Ozone Episodes: A Comparison Study

For the purpose of short-term forecasting of high ozone concentration episodes stochastic models have been suggested and developed in the literature. The present paper compares the quality of forecasts produced by a grey box and a component time-series model. The summer ozone patterns for three European urban areas (two continental and one mediterranean) are processed. By means of forecast performance indices according to EC and WHO guidelines, the following features of the models could be found: The grey box model is highly adaptive and produces forecasts with low error variance that increases with the time horizon of forecast. The component model is more 'stiff' that results in a higher forecast-error variance and poorer adaption in detail. The forecast horizon, however, could be enlarged with this model. The accuracy of predicting threshold exceedance is similar for both models. This can be understood from the assumption of a cyclical time development of ozone that was made for both models.     

Occurrence of psychoactive compounds and their metabolites in groundwater downgradient of a decommissioned sewage farm in Berlin (Germany)

Purpose

Psychoactive compounds??meprobamate, pyrithyldione, primidone, and its metabolites, phenobarbital, and phenylethylmalonamide??were detected in groundwater within the catchment area of a drinking water treatment plant located downgradient of a former sewage farm in Berlin, Germany. The aim of this study was to investigate the distribution of the psychoactive compounds in anoxic groundwater and to assess the risk of drinking water contamination. Groundwater age was determined to achieve a better understanding of present hydrogeological conditions.

Methods

A large number of observation and production wells were sampled. Samples were analyzed using solid-phase extraction and ultrahigh-performance liquid chromatography?Ctandem mass spectrometry. Groundwater age was estimated using the helium?Ctritium (³He?C³H) dating method.

Results

Concentrations of psychoactive compounds up to 1???g/L were encountered in the contamination plume. Generally, concentrations of phenobarbital and meprobamate were the highest. Elevated concentrations of the analytes were also detected in raw water from abstraction wells located approximately 2.5?km downgradient of the former sewage farm. Concentrations in the final drinking water were below the limit of quantification owing to dilution. The age of shallow groundwater samples ranged from years to a decade, whereas groundwater was up to four decades old at 40?m below ground. Concentrations of the compounds increased with groundwater age.

Conclusions

Elevated concentrations of psychoactive drugs indicate a strong persistence of these compounds in the environment under anoxic aquifer conditions. Results suggest that the heritage of sewage irrigation will affect raw water quality in the area for decades. Therefore, further monitoring of raw and final drinking water is recommended to ensure that contaminant concentrations remain below the health-based precautionary value.     

Truncated Lévy flights and agenda-based mobility are useful for the assessment of personal human exposure

Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Lévy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane.     

Determination of lindane leachability in soil-biosolid systems and its bioavailability in wheat plants

The leachability of lindane from different biosolid amended soils was determined and compared to its bioavailability. Sand, soil, and a mixture of soil-sand (1:1 w/w) were spiked with lindane, blended with different amounts of biosolids, and subjected to a leaching process with water that lasted for 1-28 d. This procedure is in accordance with ISO/TS 21268-1: 2007. After these batch tests, lindane was extracted from the leachates using three different solvent-free microextraction techniques, including solid phase microextraction (SPME), stir-bar sorptive extraction (SBSE), and silicone rod extraction (SRE). The amount of lindane was determined with thermal desorption and gas chromatography coupled to mass spectrometry (GC-MS). The efficiencies of the three microextraction techniques were statistically different, and the efficiency could be related to the amount of polydimethylsiloxane (PDMS) in each extraction device. However, all of the techniques provide data that shows that the leachability of lindane is dependent on the amount of organic matter contained in the matrix.The results of the lindane leachability assay were compared to the bioavailability of lindane, which was determined by measuring the amount of lindane that accumulated in the roots of wheat plants grown in similar soil-biosolid systems.It was confirmed that the amount of organic matter in the matrix is a determining factor for lindane immobilization. The presence of biosolids decreases the mobility of lindane in all of the systems under study. Similarly, increasing biosolid concentrations in the soil significantly decreased the bioavailability of lindane and, consequently, plant absorption.The good correlation (R² = 0.997) between the leachability of lindane from the matrix and plant absorption of lindane indicates that the proposed biomimetic methodology can predict the bioavailability of lindane in a time period as short as 7 d.The results of this work confirm that amending contaminated soils with biosolids is beneficial for immobilizing lindane and helps prevent the percolation of lindane through the soil profile and into groundwater.     

Behaviour and redox sensitivity of pharmaceutical residues during bank filtration - Investigation of residues of phenazone-type analgesics

The behaviour of residues of phenazone-type pharmaceuticals during bank filtration was investigated at a field site in Berlin, Germany, where bank-filtered water is used for drinking water production. The concentrations of the pharmaceutical residues in the shallow, young bank filtrate (travel times相似文献