Gartiser S.,Hydrotox GmbH |
Hafner C.,Hydrotox GmbH |
Kronenberger-Schafer K.,Hydrotox GmbH |
Happel O.,DVGW Technologiezentrum Wasser TZW |
And 2 more authors.
Environmental Science and Pollution Research | Year: 2012
Many pharmaceuticals and related metabolites are not efficiently removed in sewage treatment plants and enter into surface water. There, they might be subject of drinking water abstraction and treatment by ozonation. In this study, a systematic approach for producing and effect-based testing of transformation products (TPs) during the drinking water ozonation process is proposed. For this, two pharmaceutical parent substances, three metabolites and one environmental degradation product were investigated with respect to their biodegradability and fate during drinking water ozonation. The Ames test (TA98, TA100) was used for the identification of mutagenic activity present in the solutions after testing inherent biodegradability and/or after ozonation of the samples. Suspicious results were complemented with the umu test. Due to the low substrate concentration required for ozonation, all ozonated samples were concentrated via solid phase extraction (SPE) before performing the Ames test. With the exception of piracetam, all substances were only incompletely biodegradable, suggesting the formation of stable TPs. Metformin, piracetam and guanylurea could not be removed completely by the ozonation process. We received some evidence that technical TPs are formed by ozonation of metformin and piracetam, whereas all tested metabolites were not detectable by analytical means after ozonation. In the case of guanylurea, one ozonation TP was identified by LC/MS. None of the experiments showed an increase of mutagenic effects in the Ames test. However, the SPE concentration procedure might lead to false-positive results due to the generation of mutagenic artefacts or might lead to false-negative results by missing adequate recovery efficiency. Thus, these investigations should always be accompanied by process blank controls that are carried out along the whole ozonation and SPE procedure. The study presented here is a first attempt to investigate the significance of transformation products by a systematic approach. However, the adequacy and sensitivity of the methodology need to be further investigated. The approach of combining biodegradation and ozonation with effect-based assays is a promising tool for the early detection of potential hazards from TPs as drinking water contaminants. It can support the strategy for the evaluation of substances and metabolites in drinking water. A multitude of possible factors which influence the results have to be carefully considered, among them the selectivity and sensibility of the mutagenicity test applied, the extraction method for concentrating the relevant compounds and the biocompatibility of the solvent. Therefore, the results have to be carefully interpreted, and possible false-negative and false-positive results should be considered. © 2012 Springer-Verlag.
Sacher F.,DVGW Technologiezentrum Wasser TZW
Chemie in Unserer Zeit | Year: 2013
Drinking water surveillance is always affected by scientific findings and innovation in analytical instrumentation. Stateof- the-art drinking water monitoring will take advantage of these developments to safe-guard water quality. Recent trends in modern drinking water laboratories are increasing automation, the introduction of high-end instrumentation and new procedures for analysis of chemical and microbiological contaminants, the appearance of new (emerging) parameters, the introduction of effect-related analytical methods (biotests) and on-line systems for operational control and early-warning purposes. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Meffe R.,Free University of Berlin |
Kohfahl C.,Free University of Berlin |
Holzbecher E.,University of Gottingen |
Massmann G.,Free University of Berlin |
And 2 more authors.
Water Research | Year: 2010
A finite element model was set-up to determine degradation rate constants for p-TSA during rapid sand filtration (RSF). Data used for the model originated from a column experiment carried out in the filter hall of a drinking water treatment plant in Berlin (Germany). Aerated abstracted groundwater was passed through a 1.6 m long column-shaped experimental sand filter applying infiltration rates from 2 to 6 m h-1. Model results were fitted to measured profiles and breakthrough curves of p-TSA for different infiltration rates using both first-order reaction kinetics and Michaelis-Menten kinetics. Both approaches showed that degradation rates varied both in space and time. Higher degradation rates were observed in the upper part of the column, probably related to higher microbial activity in this zone. Measured and simulated breakthrough curves revealed an adaption phase with lower degradation rates after infiltration rates were changed, followed by an adapted phase with more elevated degradation rates. Irrespective of the mathematical approach and the infiltration rate, degradation rates were very high, probably owing to the fact that filter sands have been in operation for decades, receiving high p-TSA concentrations with the raw water. © 2009 Elsevier Ltd. All rights reserved.
Stoll C.,DVGW Technologiezentrum Wasser TZW |
Sidhu J.P.S.,CSIRO |
Sidhu J.P.S.,University of The Sunshine Coast |
Tiehm A.,DVGW Technologiezentrum Wasser TZW |
And 2 more authors.
Environmental Science and Technology | Year: 2012
The prevalence and proliferation of antibiotic resistant bacteria is profoundly important to human health, but the extent to which aquatic environments contribute toward the dissemination of antibiotic resistant genes (ARGs) is poorly understood. The prevalence of 24 ARGs active against eight antibiotic classes (β-lactams, aminoglycosides, glycopeptides, chloramphenicols, tetracycline, macrolides, trimethoprim, and sulfonamides) was evaluated in surface water samples collected from Germany and Australia with culture independent methods. The ARGs most frequently detected both in Germany and Australia were sulI, sulII (77-100%), and dfrA1 (43-55%) which code for resistance to sulfonamide and trimethoprim. Macrolides resistance gene ermB was relatively more prevalent in the surface water from Germany (68%) than Australia (18%). In contrast, the chloramphenicol resistance gene catII was more frequently detected in Australia (64%) than Germany (9%). Similarly, β-lactams resistance gene ampC was more prevalent in the samples from Australia (36%) than Germany (19%). This study highlights wide distribution of ARGs for sulfonamide, trimethoprim, macroline, β-lactams and chloramphenicol in the aquatic ecosystems. Aquatic ecosystems can therefore be reservoirs of ARGs genes which could potentially be transferred from commensal microorganisms to human pathogens. © 2012 American Chemical Society.
Kreissel K.,DVGW Technologiezentrum Wasser TZW |
Bosl M.,DVGW Technologiezentrum Wasser TZW |
Lipp P.,DVGW Technologiezentrum Wasser TZW |
Franzreb M.,Karlsruhe Institute of Technology |
Hambsch B.,DVGW Technologiezentrum Wasser TZW
Water Science and Technology | Year: 2012
To determine the removal efficiency of ultrafiltration (UF) membranes for nano-particles in the size range of viruses the state of the art uses challenge tests with virus-spiked water. This work focuses on bench-scale and semi-technical scale experiments. Different experimental parameters influencing the removal efficiency of the tested UF membrane modules were analyzed and evaluated for benchand semi-technical scale experiments. Organic matter in the water matrix highly influenced the removal of the tested bacteriophages MS2 and phiX174. Less membrane fouling (low ΔTMP) led to a reduced phage reduction. Increased flux positively affected phage removal in natural waters. The tested bacteriophages MS2 and phiX174 revealed different removal properties. MS2, which is widely used as a model organism to determine virus removal efficiencies of membranes, mostly showed a better removal than phiX174 for the natural water qualities tested. It seems that MS2 is possibly a less conservative surrogate for human enteric virus removal than phiX174. In bench-scale experiments log removal values (LRV) for MS2 of 2.5-6.0 and of 2.5-4.5 for phiX174 were obtained for the examined range of parameters. Phage removal obtained with differently fabricated semitechnical modules was quite variable for comparable parameter settings, indicating that module fabrication can lead to differing results. Potting temperature and module size were identified as influencing factors. In conclusion, careful attention has to be paid to the choice of experimental settings and module potting when using bench-scale or semi-technical scale experiments for UF membrane challenge tests. © IWA Publishing 2012.