Vattenkvalitet

This document is applicable to lakes, which are water bodies occupying one or more basins with surface areas typically greater than 1 ha (0,01 km2) and maximum depths (at mean water level) greater than 1 m. All types of permanent and temporary lakes, including natural, modified and artificial, freshwater and brackish, except for those systems which regularly connect to the sea, are included in this document. Based on these criteria, it can be estimated that there are at least 500 000 natural lakes across Europe, most of which are located in the glaciated landscapes in northern and western provinces and in Scandinavia. Lakeland districts also occur locally in areas such as large river catchments (e.g. the Danubian plain) and around the Alps. Elsewhere, naturally occurring lakes are relatively sparse and in such areas reservoirs or pits are more common. This document is designed to: a) support environmental and conservation agencies in meeting the monitoring requirements of the WFD (Article 8, Annex II and Annex V); b) generate data sets appropriate for monitoring and reporting of Natura 2000 sites designated under the Habitats Directive and the Birds Directive; c) provide information supporting other environmental reporting requirements (e.g. in relation to biodiversity or environmental impact assessment); d) support lake management and restoration initiatives. This document: e) defines the key term of ‘hydromorphology’ and other terms relating to the morphological characteristics of lakes and their hydrological regimes; f) details essential features and processes of lakes that should be characterized as part of a hydromorphological survey and for determining the hydromorphological condition of a lake; g) identifies and defines the key pressures affecting European lakes; h) provides guidance on strategies for collecting hydromorphological data depending on resources available and the anticipated use of the assessment; a hierarchy of approaches is recognized from the ‘overview method’ utilizing existing databases, maps and remote sensing data through to recognized field-based survey techniques such as Lake Habitat Survey (LHS) [3]; i) offers guidance on data presentation; j) establishes guidance on data quality assurance issues. This document does not deal with biological assessments in lakes such as the presence or absence of individual species or community composition, nor does it attempt to link specific hydromorphological features with their associated biological communities or to create a classification based on such links. However, it is relevant where plants or other organisms form significant structural elements of the habitat (e.g. a gradation from riparian to littoral vegetation). With respect to the WFD, the hydromorphological condition of a lake only contributes to its status classification at high ecological status (HES). Hydromorphological conditions are not defined for good and moderate status but shall be sufficient to support the biological elements. However, some countries are now beginning to classify lakes according to their hydromorphology. The information gathered by using this standard can provide a basis for classification, but this classification is the subject of EN 16870 and not EN 16039.

This document specifies methods used to determine the concentration of plutonium and neptunium isotopes in water by inductively coupled plasma mass spectrometry (ICP-MS) (239Pu, 240Pu, 241Pu and 237Np). The concentrations obtained can be converted into activity concentrations of the different isotopes[9]. Due to its relatively short half-life and 238U isobaric interference, 238Pu can hardly be measured by this method. To quantify this isotope, other techniques can be used (ICP-MS with collision-reaction cell, ICP-MS/MS with collision-reaction cell or chemical separation). Alpha spectrometry measurement, as described in ISO 13167[10], is currently used[11]. This method is applicable to all types of water having a saline load less than 1 g·l−1. A dilution of the sample is possible to obtain a solution having a saline load and activity concentrations compatible with the preparation and the measurement assembly. A filtration at 0,45 μm is needed for determination of dissolved nuclides. Acidification and chemical separation of the sample are always needed. The limit of quantification depends on the chemical separation and the performance of the measurement device. This method covers the measurement of those isotopes in water in activity concentrations between around[12][13]: — 1 mBq·l−1 to 5 Bq·l−1 for 239Pu, 240Pu and 237Np; — 1 Bq·l−1 to 5 Bq·l−1 for 241Pu. In both cases, samples with higher activity concentrations than 5 Bq·l−1 can be measured if a dilution is performed before the chemical separation. It is possible to measure 241Pu following a pre-concentration step of at least 1 000.