Herrmann F.,Jülich Research Center |
Berthold G.,Hessian Agency for the Environment and Geology HLUG |
Fritsche J.-G.,Hessian Agency for the Environment and Geology HLUG |
Kunkel R.,Jülich Research Center |
And 2 more authors.
Environmental Earth Sciences | Year: 2012
A regional conceptual hydrogeological model has been developed for evaluating residence times of both, percolate water in the unsaturated zone and groundwater in upper aquifers. The model is based on digitally geo-data bases available at the regional level and has been applied for the entire Federal State of Hesse (Germany) with a spatial resolution of 60 × 60 m. Residence times determined for unconsolidated rock areas typically ranged between 10 and 25 years, whereas residence times of <5 years were assessed for consolidated rock areas. With regard to the implementation of the EU Water Framework Directive, the determined residence times may help to assess the time periods between the introduction of well-targeted groundwater protection measures and their impact on groundwater and surface water quality, respectively. © 2012 Springer-Verlag.
Menberg K.,Karlsruhe Institute of Technology |
Bayer P.,ETH Zurich |
Zosseder K.,TU Munich |
Rumohr S.,Hessian Agency for the Environment and Geology HLUG |
Blum P.,Karlsruhe Institute of Technology
Science of the Total Environment | Year: 2013
Little is known about the intensity and extension of subsurface urban heat islands (UHI), and the individual role of the driving factors has not been revealed either. In this study, we compare groundwater temperatures in shallow aquifers beneath six German cities of different size (Berlin, Munich, Cologne, Frankfurt, Karlsruhe and Darmstadt). It is revealed that hotspots of up to +20K often exist, which stem from very local heat sources, such as insufficiently insulated power plants, landfills or open geothermal systems. When visualizing the regional conditions in isotherm maps, mostly a concentric picture is found with the highest temperatures in the city centers. This reflects the long-term accumulation of thermal energy over several centuries and the interplay of various factors, particularly in heat loss from basements, elevated ground surface temperatures (GST) and subsurface infrastructure. As a primary indicator to quantify and compare large-scale UHI intensity the 10-90%-quantile range UHII10-90 of the temperature distribution is introduced. The latter reveals, in comparison to annual atmospheric UHI intensities, an even more pronounced heating of the shallow subsurface. © 2012 Elsevier B.V.
Regnery J.,Goethe University Frankfurt |
Puttmann W.,Goethe University Frankfurt |
Merz C.,Leibniz Center for Agricultural Landscape Research |
Berthold G.,Hessian Agency for the Environment and Geology HLUG
Journal of Environmental Monitoring | Year: 2011
Occurrence and distribution of chlorinated and non-chlorinated organophosphates in 72 groundwater samples from Germany under different recharge/infiltration conditions were investigated. Tris(2-chloro-1-methylethyl) phosphate (TCPP) and tris(2-chloroethyl) phosphate (TCEP) were the most frequently detected organophosphates in groundwater samples. Highest individual organophosphate concentrations (>0.1 g L-1) were determined in groundwater polluted by infiltrating leachate and groundwater recharged via riverbank filtration of organophosphate-loaded recipients. In samples from springs and deep groundwater monitoring wells that are not affected by surface waters, organophosphate concentrations were mostly below the limit of detection. The occurrence (3-9 ng L-1) of TCPP and TCEP in samples from aquifers with groundwater ages between 20 and 45 years indicates the persistence of both compounds within the aquifer. At urban sites organophosphate-loaded precipitation, surface runoff, and leakage of wastewater influenced groundwater quality. For rural sites, where groundwater recharge is only influenced by precipitation, organophosphates were very rarely detectable in groundwater. © The Royal Society of Chemistry 2011.
Bonn B.,Goethe University Frankfurt |
Bonn B.,Institute for Advanced Sustainable Studies |
Sun S.,Goethe University Frankfurt |
Sun S.,Max Planck Institute for Chemistry |
And 6 more authors.
Atmospheric Measurement Techniques | Year: 2013
In this study we report the set-up of a novel twin chamber technique that uses the comparative method and establishes an appropriate connection of atmospheric and laboratory methods to broaden the tools for investigations. It is designed to study the impact of certain parameters and gases on ambient processes, such as particle formation online, and can be applied in a large variety of conditions. The characterisation of both chambers proved that both chambers operate identically, with a residence time xT (COMPASS1) Combining double low line 26.5 ± 0.3 min and xT (COMPASS2) Combining double low line 26.6 ± 0.4 min, at a typical flow rate of 15 L min-1 and a gas leak rate of (1.6 ± 0.8) × 10−5 s-1. Particle loss rates were found to be larger (due to the particles' stickiness to the chamber walls), with an extrapolated maximum of 1.8 × 10−3 s-1 at 1 nm, i.e. a hundredfold of the gas leak rate. This latter value is associated with sticky non-volatile gaseous compounds, too. Comparison measurement showed no significant differences. Therefore operation under atmospheric conditions is trustworthy. To indicate the applicability and the benefit of the system, a set of experiments was conducted under different conditions, i.e. urban and remote, enhanced ozone and terpenes as well as reduced sunlight. In order to do so, an ozone lamp was applied to enhance ozone in one of two chambers; the measurement chamber was protected from radiation by a first-aid cover and volatile organic compounds (VOCs) were added using a small additional flow and a temperature-controlled oven. During the elevated ozone period, ambient particle number and volume increased substantially at urban and remote conditions, but by a different intensity. Protection of solar radiation displayed a clear negative effect on particle number, while terpene addition did cause a distinct daily pattern. E.g. adding β pinene particle number concentration rose by 13% maximum at noontime, while no significant effect was observable during darkness. Therefore, the system is a useful tool for investigating local precursors and the details of ambient particle formation at surface locations as well as potential future feedback processes.©Author(s) 2013. CC Attribution 3.0 License.