Listen
21 Ergebnisse
Filter
Einstellungen
Suchergebnisse
Veröffentlichung Chemical analysis of the quality of water for human consumption(2013)The following is a proposal for the revision of method-performance characteristics for the chemical analysis of water intended for human consumption under the Drinking Water Directive (DWD) 98/83/EC.According to the proposal, the EN ISO/IEC 17025 Standard should be introduced into the Directive, and the performance characteristics, measurement uncertainty (MU) and limit of quantification (LOQ) should replace or complement those currently in use (i.e. trueness, precision and limit of detection). Minimum performance characteristics for MU and LOQ are also suggested for each chemical parameter.
Quelle: http://www.sciencedirect.com/Veröffentlichung Drinking-Water Criteria (Safety, Quality, and Perception)(2014) Dieter, Hermann H.Veröffentlichung Veröffentlichung Removal of indigenous coliphages and enteric viruses during riverbank filtration from highly polluted river water in Delhi (India)(2014)Emerging countries frequently afflicted by waterborne diseases require safe and cost-efficient production of drinking water, a task that is becoming more challenging as many rivers carry a high degree of pollution. A study was conducted on the banks of the Yamuna River, Delhi, India, to ascertain if riverbank filtration (RBF) can significantly improve the quality of the highly polluted surface water in terms of virus removal (coliphages, enteric viruses). Human adenoviruses and noroviruses, both present in the Yamuna River in the range of 10(5) genomes/100 mL, were undetectable after 50 m infiltration and approximately 119 days of underground passage. Indigenous somatic coliphages, used as surrogates of human pathogenic viruses, underwent approximately 5 log10 removal after only 3.8 m of RBF. The initial removal after 1 m was 3.3 log10, and the removal between 1 and 2.4 m and between 2.4 and 3.8 m was 0.7 log10 each. RBF is therefore an excellent candidate to improve the water situation in emerging countries with respect to virus removal. © Copyright 2014 MedlineVeröffentlichung Current approaches to cyanotoxin risk assessment and risk management around the globe(2014)Toxic cyanobacteria became more widely recognized as a potential health hazard in the 1990s, and in 1998 the World Health Organization (WHO) first published a provisional Guideline Value of 1 ìg L-1for microcystin-LR in drinking-water. In this publication we compare risk assessment and risk management of toxic cyanobacteria in 17 countries across all five continents. We focus on the three main (oral) exposure vehicles to cyanotoxins: drinking-water, water related recreational and freshwater seafood. Most countries have implemented the provisional WHO Guideline Value, some as legally binding standard, to ensure the distribution of safe drinking-water with respect to microcystins. Regulation, however, also needs to address the possible presence of a wide range of other cyanotoxins and bioactive compounds, for which no guideline values can be derived due to insufficient toxicological data. The presence of microcystins (commonly expressed as microcystin-LR equivalents) may be used as proxy for overall guidance on risk management, but this simplification may miss certain risks, for instance from dissolved fractions of cylindrospermopsin and cyanobacterial neurotoxins. An alternative approach, often taken for risk assessment and management in recreational waters, is to regulate cyanobacterial presence - as cell numbers or biomass - rather than individual toxins. Here, many countries have implemented a two or three tier alert level system with incremental severity. These systems define the levels where responses are switched from Surveillance to Alert and finally to Action Mode and they specify the short-term actions that follow. Surface bloom formation is commonly judged to be a significant risk because of the elevated concentration of microcystins in a scum. Countries have based their derivations of legally binding standards, guideline values, maximally allowed concentrations (or limits named otherwise) on very similar scientific methodology, but underlying assumptions such as bloom duration, average body size and the amount of water consumed while swimming vary according to local circumstances. Furthermore, for toxins with incomplete toxicological data elements of expert judgment become more relevant and this also leads to a larger degree of variation between countries thresholds triggering certain actions. Cyanobacterial blooms and their cyanotoxin content are a highly variable phenomenon, largely depending on local conditions, and likely concentrations can be assessed and managed best if the specific conditions of the locality are known and their impact on bloom occurrence are understood. Risk Management Frameworks, such as for example the Water Safety Plan concept of the WHO and the ´bathing water profile of the European Union are suggested to be effective approaches for preventing human exposure by managing toxic cyanobacteria from catchment to consumer for drinking water and at recreational sites.
© www.sciencedirect.comVeröffentlichung Round robin test for odour testing of migration waters(2015) Günther, Herbert; Rapp, ThomasFor a round robin test for EN 1420-1 (Odour assessment for organic materials in contact with drinking water) with 14 contributing laboratories from 10 European countries segments of a plastic pipe were sent to the laboratories which performed a migration test and an odour analysis of the migration waters (water that had contact with the organic material) according to the procedure described in the standard from 1999. In addition reference substances (Methyl tert-butyl ether, 1-butanol and hexanal) were investigated for their suitability to qualify the panels and the individual panellists. Methyl tert-butyl ether (MtBE) and 1-butanol proved to be suitable for this purpose, whereas hexanal showed a wide distribution of the individual odour threshold concentrations. Both possible testing options (unforced and forced choice) were performed and gave similar results. However, with respect to the qualification of the panellists and the data analysis the unforced choice procedure showed advantages. As human olfactory perception is used for the analysis, the reproducibility and the comparability between laboratories is of particular concern. For the pipe material the TON results of the different laboratories were in a range of ş1.5 dilutions based on a dilution factor of 2. This might be improved by taking the individual sensitivities of the panellists into account more strongly. Appropriate measures for the improvement of the test method appear to be the use of the proposed reference substances for the training of the panellists as well as the auditing and the selection of the panellists. The results of this round robin test are used in the revision process of the standard.Quelle: http://www.sciencedirect.comVeröffentlichung Mikrobiologische Überwachung der Trinkwasserqualität(2016) Feuerpfeil, Irmgard; Hummel, AnnetteDrinking water is the most important food for humans. However, drinking water can also be the source of infections caused by waterborne pathogenic microorganisms. Occurrence of these microorganisms may not only cause single infections but also more or less great epidemics due to the volume of water consumed. For the protection of people's health the German government has provided the bacteriological investigation and surveillance of drinking water in public water distribution systems for more than 100 years to prevent infections. For this indicator organisms are used to detect and estimate the contamination level of drinking water.Veröffentlichung Mikrobiologische Überwachung der Trinkwasserqualität(2016) Feuerpfeil, Irmgard; Hummel, AnnetteDrinking water is the most important food for humans. However, drinking water can also be the source of infections caused by waterborne pathogenic microorganisms. Occurrence of these microorganisms may not only cause single infections but also more or less great epidemics due to the volume of water consumed. For the protection of people's health the German government has provided the bacteriological investigation and surveillance of drinking water in public water distribution systems for more than 100 years to prevent infections. For this indicator organisms are used to detect and estimate the contamination level of drinking water.Veröffentlichung A hierarchical testing strategy for micropollutants in drinking water regarding their potential endocrine-disrupting effects - health-related indicator values(2017) Grummt Tamara; Redelstein, Regine; Kuckelkorn, Jochen; Heide, Timon; Kunze, JenniferVeröffentlichung Modelling migration of substances from polymers into drinking water(2017) Mercea, P.V.; Kalisch, A.; Ulrich, M.; Schuster, RamonaIn a first part of this work the permeation through and diffusion/migration from high density polyethylene,polybutylene, polypropylene and cross linked polyethylene films was investigated experimentally with three different methods to determine diffusion coefficients in these polyolefins for a series of additives, their degradation products and other organic substances in the 20-60 ˚C temperature range. The experimental methods used were dynamic permeation through additive free the polymer films, kinetic desorption from additivated films into water and kinetic migration from additivated into additive free polymer films. It was found that in general the temperature dependence of the obtained diffusion coefficients was well represented by the Arrhenius law. Some of these results also suggested that the contact of the polyolefins with water had an influence on the magnitude of the diffusion coefficients and on their apparent activation energy of diffusion.In the second part of this work the obtained pools of diffusion coefficients for each of the investigated polymers were used to develop an approach to estimate theoretically and without any further experimentation "conservative" diffusion coefficients for any organic substance, with molecular mass ranging from 50 to 1250 g/mol, diffusing in these polymers at temperatures between 15 and 85 ˚C. The possibility to estimate such conservative diffusion coefficients is very important when it comes to use efficiently migration modelling as an alternative method to test the compliance of polymeric articles with the existing national and/or European standards for drinking water. The use of polymer specific diffusion coefficients in migration modelling is required in the framework of the "Migration modelling guideline" recommendation of the German Environment Agency. Quelle: https://www.sciencedirect.com/
- «
- 1 (current)
- 2
- 3
- »