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Hoss S.,Ecossa | Ahlf W.,TU Hamburg - Harburg | Bergtold M.,BASF | Bluebaum-Gronau E.,Federal Institute of Hydrology | And 8 more authors.
Environmental Toxicology and Chemistry | Year: 2012

A ring test was carried out within the standardization process of ISO 10872 to evaluate the precision of the toxicity test for the nematode Caenorhabditis elegans. Eight different laboratories tested aqueous solutions of the reference substance benzylcetyldimethylammonium chloride as well as native sediments and soils for toxic effects on the growth and reproduction of C. elegans. Validity criteria were met in all laboratories. Average median- and low-effect concentrations were determined to be 15.1 mg L-1 (EC50) and 8.7 mg L-1 (EC10) for growth and 7.5 mg L-1 (EC50) and 3.8 mg L-1 (EC10) for reproduction of C. elegans, with ECx values showing a high degree of reproducibility (CVR: <21% and <11% for EC10 and EC50, respectively) and repeatability (CVr: <20% and <7% for EC10 and EC50, respectively). The toxic effects of the sediments and soils revealed by the different laboratories were well related to each samples' degree of chemical contamination. Moreover, the effects showed an acceptable reproducibility (CVR: 5-33% and 0-28% for growth and reproduction, respectively) and repeatability (CVr: 3-13% and 0-12% for growth and reproduction, respectively). The present study confirms that the toxicity test with C. elegans according to ISO 10872 is a reliable and precise tool to assess the toxicity of aqueous media, freshwater sediments, and soils. © 2012 SETAC.

Gellert G.,North Rhine Westphalia State Agency for Nature Environment and Consumer Protection | Pottgiesser T.,Umweltburo Essen | Euler T.,North Rhine Westphalia State Agency for Nature Environment and Consumer Protection
Environmental Monitoring and Assessment | Year: 2014

Fifteen years ago, the first mapping guidelines for the recording and evaluation of river physical habitat quality in Germany, closely following the Länder Arbeitsgemeinschaft Wasser (LAWA) field survey, have been published. In light of this experience, a revised version has now been developed for North Rhine-Westphalia (West Germany). For the assessment, the streams are divided into segments serving as survey units. The survey is performed primarily in the field from the mouth to the source by an on-site recording of data. Defined reference conditions of the relevant morphological stream types serve as basis of the evaluation. Two evaluation procedures are carried out independently to validate the quality of the data. The proven basic concept operates as follows: the local scale habitat variables are grouped into 31 single parameters, which are then aggregated into six main parameters. These can further be aggregated into three zones: streambed, banks and adjacent land. The main modifications of the presented version are the following: (1) a larger differentiation of morphological stream types and (2) a higher level of detail concerning the mapping of relevant habitat characteristics. The last point allows additional evaluation options related to the morphological needs of the instream biota and a differentiated survey of anthropogenic degradation. Despite all modifications, the comparability with previous surveys has been largely maintained. By qualitative comparison of this method with other European mapping guidelines, different concepts of hydromorphological mapping are finally discussed. © 2014 Springer International Publishing.

Gellert G.,North Rhine Westphalia State Agency for Nature Environment and Consumer Protection | Behrens S.,North Rhine Westphalia State Agency for Nature Environment and Consumer Protection | Raschke M.,North Rhine Westphalia State Agency for Nature Environment and Consumer Protection
Water and Environment Journal | Year: 2012

Streams in North Rhine-Westphalia (Germany) are frequently impacted by hydromorphological degradation leading to a loss of sensitive species and a reduction in diversity. These findings mean that the final objective of the European Water Framework Directive to achieve the good ecological status will be failed for a large number of streams. In a holistic approach, a new concept, considering the cost efficiency, has been developed to enhance habitats by morphological changes. This guide serves as a basis for stream restoration projects. The theoretical background is that near-natural sections influence adjacent sections of medium habitat quality positively by migration of type-specific sensitive organisms. The preconditions are a local taxa richness in the catchment area, the reduction of nutrients and organic matter, and the guarantee of free movement. This so-called 'spreading effect' can be measured upstream and downstream. The length of by these means valourized sections depends on the stream type and on the biological quality component. © 2012 The Authors. Water and Environment Journal © 2012 CIWEM.

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