Geyer, Tobias

[["dc.bibliographiccitation.firstpage","251"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Grundwasser"],["dc.bibliographiccitation.lastpage","262"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:32:14Z"],["dc.date.available","2018-11-07T09:32:14Z"],["dc.date.issued","2014"],["dc.description.abstract","In the presented work the occurrence of organic micro-pollutants is discussed for two karst areas with different geological characteristics and land-use patterns. Within an urban moderately karstified catchment with a large number of local input sources (e.g. contaminated sites, sewer leakages), a greater variety of micro-pollutants is found compared to a rural area. Mostly the concentrations of these compounds decrease below quantification limits before emerging at the spring and can therefore only be detected by a comprehensive network of sampling points. Springs show the presence of micro-pollutants, either recently applied in large amounts or characterized by high persistence. At the outlet of a highly karstified and consequently highly permeable aquifer readily biodegradable compounds are detected. Due to high groundwater flow velocities investigations of micro-pollutants require a highly resolved monitoring. Therefore, beside substance properties, also hydrogeological characteristics affect the spectrum of detectable micro-pollutants."],["dc.identifier.doi","10.1007/s00767-014-0264-6"],["dc.identifier.isi","000345078800003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31709"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.issn","1432-1165"],["dc.relation.issn","1430-483X"],["dc.title","Application of organic micro-pollutants for the characterisation of two karst systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","395"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Water Research"],["dc.bibliographiccitation.lastpage","402"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Geyer, Tobias"],["dc.date.accessioned","2018-11-07T09:14:02Z"],["dc.date.available","2018-11-07T09:14:02Z"],["dc.date.issued","2012"],["dc.description.abstract","Contamination from untreated wastewater leakage and related bacterial contamination poses a threat to drinking water quality. However, a quantification of the magnitude of leakage is difficult. The objective of this work is to provide a highly sensitive methodology for the estimation of the mass of untreated wastewater entering karst aquifers with rapid recharge. For this purpose a balance approach is adapted. It is based on the mass flow of caffeine in spring water, the load of caffeine in untreated wastewater and the daily water consumption per person in a spring catchment area. Caffeine is a source-specific indicator for wastewater, consumed and discharged in quantities allowing detection in a karst spring. The methodology was applied to estimate the amount of leaking and infiltrating wastewater to a well investigated karst aquifer on a daily basis. The calculated mean volume of untreated wastewater entering the aquifer was found to be 2.2 +/- 0.5 m(3) d(-1) (undiluted wastewater). It corresponds to approximately 0.4% of the total amount of wastewater within the spring catchment. (C) 2011 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Federal Ministry of Education and Research [02WM1081, 02WRS1277A]"],["dc.identifier.doi","10.1016/j.watres.2011.11.003"],["dc.identifier.isi","000299609400014"],["dc.identifier.pmid","22104295"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27307"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0043-1354"],["dc.title","Caffeine as an indicator for the quantification of untreated wastewater in karst systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5381"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Water Research"],["dc.bibliographiccitation.lastpage","5388"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Geyer, Tobias"],["dc.date.accessioned","2018-11-07T09:04:37Z"],["dc.date.available","2018-11-07T09:04:37Z"],["dc.date.issued","2012"],["dc.description.abstract","Little is known with respect to the attenuation capacity of karst aquifers. Even less is known about the risk posed by emerging micropollutants in these systems. In order to identify the attenuation potential of karst aquifers in-situ and to estimate the risk posed by micropollutants, a dualtracer test was conducted in this study in order to investigate differential transport in the subsurface: The reactive compound caffeine was used as a tracer to indicate the attenuation capacity within the aquifer in-situ. Due to the low limit of quantification, only small amounts of caffeine needed to be injected. To calibrate a model and to visualize the attenuation of caffeine a conservative reference tracer (uranine) is injected simultaneously. The methodology is tested in a well-characterised karst system in southwest Germany. The results indicate a significantly higher attenuation rate than was expected for karst aquifers. The attenuation is decribed as a first-order process. The corresponding half-life is 104 h. This low half-life suggests that a generally assumed low natural attenuation capacity of karst aquifers is unjustified. The observed mass loss of caffeine illustrates the potential of caffeine to be used as reactive tracer for indicating in-situ attenuation capacity within highly hydraulically conductive systems, such as karst aquifers. Due to the high attenuation rate of caffeine it does not pose a threat as a longtime contaminant. In combination with a conservative reference tracer an economical and environmentally benign method is presented in this manuscript for the in-situ determination of the attenuation capacity of highly conductive aquifer systems. (C) 2012 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Federal Ministry of Education and Research [02WRS1277A]"],["dc.identifier.doi","10.1016/j.watres.2012.07.032"],["dc.identifier.isi","000309095800046"],["dc.identifier.pmid","22877878"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/25147"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0043-1354"],["dc.title","Identification of the attenuation potential of a karst aquifer by an artificial dualtracer experiment with caffeine"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4631"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Environmental Science and Pollution Research"],["dc.bibliographiccitation.lastpage","4643"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T10:00:15Z"],["dc.date.available","2018-11-07T10:00:15Z"],["dc.date.issued","2015"],["dc.description.abstract","This study presents chances and challenges associated with the application of organic micro-pollutants (OMPs) as indicators in karst system characterization. The methodology and options of possible indications were evaluated based on the interpretation of the spatial distribution of 54 compounds in groundwater in combination with a complex geological setting consisting of multiple aquifer horizons and tectonic faults. A high variety of OMPs are released mainly in an urban area leading to concentrations of several nanograms per liter up to micrograms per liter, which are detectable using a high-performance liquid chromatography with subsequent tandem mass spectrometry (HPLC-MS/MS) method. Since characteristic patterns of spatial distribution were repeatedly observed during a 2-year observation period, important criteria of the aforementioned indicator application are fulfilled. Triazoles, compounds with recent high emission rates, could be successfully applied for the identification of flow directions and the delineation of catchment areas. Concentrations and the number of OMPs are believed to be dependent on properties of covering rock layers. Therefore, OMPs can also be used as a validation tool for vulnerability mapping. Compounds, such as triazines, persistent in the system for more than two decades, demonstrate the interaction between different parts of the aquifer system and the hydraulic characteristics of a tectonic fault zone. Such indicator potentials complement those of artificial tracer tests. Point sources of OMPs and their impact on groundwater could be identified qualitatively. In combination with the interpretation of the geological setting, the distribution of OMPs provides essential information for the development of a conceptual hydrogeological model."],["dc.identifier.doi","10.1007/s11356-014-3676-z"],["dc.identifier.isi","000350572500054"],["dc.identifier.pmid","25323407"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37761"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.issn","1614-7499"],["dc.relation.issn","0944-1344"],["dc.title","Evaluation and application of organic micro-pollutants (OMPs) as indicators in karst system characterization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","438"],["dc.bibliographiccitation.journal","The Science of The Total Environment"],["dc.bibliographiccitation.lastpage","445"],["dc.bibliographiccitation.volume","443"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:29:09Z"],["dc.date.available","2018-11-07T09:29:09Z"],["dc.date.issued","2013"],["dc.description.abstract","Fifty-four different organic micro-pollutants (OMPs) including pharmaceuticals, pesticides, corrosion inhibitors and other typical wastewater compounds such as caffeine are repeatedly analyzed in approximately fifty groundwater observation points in a complex faulted and fractured carbonate aquifer system consisting of three spring catchment areas. With the applied HPLC-MS/MS method, achieving method quantification limits (MQL) of 12-28 ng L-1, forty-four of the OMPs are detected in groundwater. Regarding the vertical distribution in the aquifer system the highest variety of OMPs occurs in the shallow aquifer. Most frequently detected compounds are atrazine together with the metabolites of several triazines, desethylatrazine (DEA) and desisopropylatrazine (DIA), the corrosion inhibitors 1H-benzotriazole and tolytriazoles and as pharmaceutical residues the anti-epileptic drug carbamazepine as well as the analgesic drug phenazone. Median OMP concentrations are in the range of 20-40 ng L-1 with occasionally and locally higher concentrations of up to 6000 ng L-1. Defined combinations of OMPs occur repeatedly in the same observation wells and allow to distinguish different input functions. The comparison of detection frequency with the number of prescribed doses gives information about the specific persistence of pharmaceuticals. The analgesic phenazone exhibits a peculiar high detection frequency, although it is recently not prescribed in significant amounts. The detection of the estrogen antagonist tamoxifen (6-17 ng L-1) in a groundwater flow system is reported for the first time. (C) 2012 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.scitotenv.2012.11.005"],["dc.identifier.isi","000315559900046"],["dc.identifier.pmid","23208277"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30949"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0048-9697"],["dc.title","Occurrence and spatial distribution of organic micro-pollutants in a complex hydrogeological karst system during low flow and high flow periods, results of a two-year study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","193"],["dc.bibliographiccitation.journal","The Science of The Total Environment"],["dc.bibliographiccitation.lastpage","200"],["dc.bibliographiccitation.volume","482"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Licha, Tobias"],["dc.date.accessioned","2018-11-07T09:39:46Z"],["dc.date.available","2018-11-07T09:39:46Z"],["dc.date.issued","2014"],["dc.description.abstract","While karst aquifers are considered as rapid flow and transport systems, their high potential for long-term storage is often ignored. However, to achieve a sustainable raw water quality for drinking water production, the understanding of this potential is highly essential. In this study, the transport dynamics of the two herbicides metazachlor and atrazine as well as a degradation product of the latter (desethylatrazine) were investigated at a karst spring over 1 year. Even 20 years after its ban in Germany, atrazine and its degradation product were almost always detectable in the spring water in the low ng L-1 range (up to 5.2 ng L-1). Metazachlor could only be detected after precipitation events, and the observed concentrations (up to 82.9 ng L-1) are significantly higher than atrazine or desethylatrazine. Comparing the dynamics of the herbicides with the inorganic ions Ca2+, Mg2+ and electrical conductivity, a positive correlation of atrazine with these parameters could be observed. From this observation, atrazine is concluded to be located within the aquifer matrix. To achieve a sustainable raw water management at karst springs, the rapidness of these systems needs to be highlighted as well as their long-term storage potential. Persistent substances or transformation products are prone to deteriorate the raw water quality for decades. (C) 2014 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.scitotenv.2014.02.117"],["dc.identifier.isi","000335625100020"],["dc.identifier.pmid","24646672"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33362"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1879-1026"],["dc.relation.issn","0048-9697"],["dc.title","Investigating the dynamics of two herbicides at a karst spring in Germany: Consequences for sustainable raw water management"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","150"],["dc.bibliographiccitation.journal","Applied Geochemistry"],["dc.bibliographiccitation.lastpage","156"],["dc.bibliographiccitation.volume","47"],["dc.contributor.author","Doummar, Joanna"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Baierl, Michael"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:36:57Z"],["dc.date.available","2018-11-07T09:36:57Z"],["dc.date.issued","2014"],["dc.description.abstract","The pharmaceutical drug carbamazepine is considered an effective wastewater marker. The varying concentration of this drug was analyzed in a mature karst spring following a precipitation event. The results show that carbamazepine is an indicator of wastewater entering the system through a fast flow pathway, leading to an increase of the drug concentrations in spring water shortly after a strong rainfall event. The analysis of the breakthrough curve of carbamazepine along with the electrical conductivity signal and major ions chemograph allowed the development of a conceptual model for precipitation event-based flow and transport in the investigated karst system. Furthermore the amount of newly recharged water and the mass of carbamazepine reaching the aquifer system during the event could be estimated using a simple mixing approach. The distance between the karst spring and the potential carbamazepine source was estimated by the combination of results from artificial tracer tests and the carbamazepine breakthrough curve. The assessment of spring responses to precipitation event using persistent drugs like carbamazepine helps assess the effect of waste water contamination at a spring and gives therefore insights to the specific vulnerability of a karst spring. (C) 2014 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.apgeochem.2014.06.004"],["dc.identifier.isi","000341340200015"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32727"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0883-2927"],["dc.title","Carbamazepine breakthrough as indicator for specific vulnerability of karst springs: Application on the Jeita spring, Lebanon"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]