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Köln, Germany

Gunten U.V.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Gunten U.V.,ETH Zurich | Salhi E.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Schmidt C.K.,Water Technology Center | And 3 more authors.
Environmental Science and Technology | Year: 2010

N,N-Dimethylsulfamide (DMS), a newly identified, ubiquitous degradation product of the fungicide tolylfluanide, has been shown to be a N-nitrosodimethylamine (NDMA) precursor during ozonation. In this study, batch ozonation experiments in ultrapure buffered water, surface water, and tap water were performed to determine the kinetics and elucidate the mechanism of NDMA formation from DMS. It was found that at circumneutral pH, DMS reacts slowly with ozone (k ≈ 20 M1 s1) and moderately with hydroxyl radicals (k = 1.5×109 M1s1). The reaction of DMS with these oxidants does not lead to NDMA. NDMA was only formed if bromide was present during ozonation of DMS-containing waters. Bromide is oxidized to hypobromous acid (HOBr) by ozone which then reacts with the primary amine of DMS to form a Br-DMS species. The rate limiting step of the formation of Br-DMS is the formation of HOBr. The reaction to form Br-DMS has an apparent second order rate constant at pH 8 of >3×104 M 1s1. The Br-DMS is transformed by ozone to NDMA and nitrate (k - 5000 M1 s1), with yields of 54% and 39%, respectively, based on the primary amine nitrogen of DMS. These reactions release bromide, making bromide a catalyst. NDMA is also formed during ozonation of DMS in the presence of hypochlorous acid (20-30% yield). The last step of NDMA formation is an intramolecular rearrangement with sulfur dioxide extrusion. On the basis of the mechanistic and kinetic information, it was possible to model NDMA formation in DMS-containing Lake Zurich water. © 2010 American Chemical Society. Source

Goen T.,Friedrich - Alexander - University, Erlangen - Nuremberg | Schmidt C.K.,RheinEnergie AG | Wilhelm M.,Ruhr University Bochum | Holzer J.,Ruhr University Bochum
International Journal of Hygiene and Environmental Health | Year: 2012

In Cologne, Germany, increased concentrations of perfluorinated compounds (PFC) have been observed in two private wells used for drinking water purposes. Both wells are located in the vicinity of a fire training area. Use of well water as a source of drinking water was prohibited by the Public Health Department of the City of Cologne. A human biomonitoring (HBM) survey was performed among all persons, who consumed water from these private wells (N=10). PFC concentrations in water of the private wells and in blood samples were analysed by tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS). Repeated water analyses (seven measurements between December 2009 and November 2010) indicated a decrease of PFOS from 8.35 to 1.60μg/l, (PFHxS: 2.36-0.15μg/l; PFOA: 0.16-0.03μg/l) in one private well. Although situated close together, PFC-concentrations in the other private well were significantly lower. PFOS-concentrations in blood samples of private well water consumers ranged from 4.8 to 295μg/l (PFHxS: 12.1-205μg/l; PFOA: 4.0-18μg/l). Although no data on the formulation of the firefighting foams applied on the fire training area is available, firefighting foams are supposed to be the most likely source of contamination. These findings give reason to track systematically the application of PFC-containing firefighting foams in order to identify contaminations of surface, ground and drinking waters. © 2011 Elsevier GmbH. Source

Schmidt C.K.,RheinEnergie AG | Raue B.,DVGW Technologiezentrum Wasser | Brauch H.-J.,DVGW Technologiezentrum Wasser | Sacher F.,DVGW Technologiezentrum Wasser
International Journal of Environmental Analytical Chemistry | Year: 2014

A novel analytical method for the trace-level determination of the organic phosphonates 1-hydroxyethane(1,1-diphosphonic acid) (HEDP), nitrilotris(methylene phosphonic acid) (NTMP), ethylenediaminetetra(methylene phosphonic acid) (EDTMP), hexamethylenediaminetetra(methylene phosphonic acid) (HDTMP) and diethylenetriaminepenta(methylene phosphonic acid) (DTPMP) in natural waters is described. Key-elements of the novel method are the destruction of the various metal complexes which are present in natural water samples by a strong cation exchange resin, the subsequent 50-fold pre-concentration of the analytes by a weak anion exchanger and their final determination by ion chromatography and inductively coupled plasma mass spectrometry. Addition of the complexing agent diethylenetriaminepentaacetic acid (DTPA) to the eluent of the anion exchanger leads to a significant improvement of the chromatographic performance for all phosphonates, but especially for EDTMP. Detection of the phosphorous species in ICP-MS is done via the molecular ion 47PO+ which exhibits high sensitivity and which is only marginally affected by interferences. Validation of the method gives excellent performance parameters with recoveries close to 100%, limits of detection below 0.1 μg/L for each individual target compound and standard deviations for replicate analyses below 10%. Application of the novel method to environmental samples shows that trace amounts of HEDP and DTPMP may be found in river waters affected by discharges of municipal or industrial wastewater treatment plants. © 2013 © 2013 Taylor & Francis. Source

Steinkamp D.,RheinEnergie AG
BWK - Energie-Fachmagazin | Year: 2011

Energy conversion has become a popular topic in the aftermath of the 3/11/2011 earthquake and tsunami in Japan. The concept has been around for ≈ 30 yr in Germany, which currently sources ≈ 20% of its electricity mix from renewable energy. Germany's early adoption of energy conversion has allowed it to address energy demand concerns. Nevertheless, there are still other energy industry-related challenges that the country needs to tackle. Source

Storck F.R.,DVGW Technologiezentrum Wasser TZW | Schmidt C.K.,RheinEnergie AG | Lange F.T.,DVGW Technologiezentrum Wasser TZW | Brauch H.-J.,DVGW Technologiezentrum Wasser TZW
GWF, Wasser - Abwasser | Year: 2013

Bank filtration sites in Germany and the United States of America were evaluated for their removal efficiency for a large set of organic trace pollutants and general principles were derived from the results. Important site-specific factors which determine the removal efficiency were mainly the redox setting, retention time, temperature, discharge of the river, and concentration of a compound in surface water. Changes of the redox setting can cause divergent effects for different compounds. Source

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