Water body profiles

The water profiles complement the regular monitoring programmes, the quantitative results of which are published here: www.elwasweb.nrw.de. It providesqualitative information on the occurrence and frequency of other organic trace substances in water bodies. This information is derived from the suspect workflow of Non-Target-Analysis. For this purpose, several samples are analysed and evaluated over a defined period of time. 

The first diagram, "Target substances", shows the frequency of occurrence of the organic trace substances found, which are already analysed in the regular monitoring of the LANUV. The diagram "Suspected target substances" shows the frequency of occurrence of trace substances that have not been analysed in any LANUV methode. The different substance groups are divided by colour.

The water profile provides an overview of constantly recurring substances present in many or all water bodies (ubiquitous substances) and water body-specific substances that should be prioritised in order to identify possible sources and take any necessary action.

For experts:

The data recorded using LC-HRMS are analysed using a database and are considered positive if the following criteria are met:

1. Accuracy of the exact mass, ± 10 ppm
2. Matching of the isotope pattern 
3. Compliance with a reference spectrum
   Optional, if available: Compliance of the retention time with the reference substance

Features are unknown components. To detect as many trace substances as possible, each sample is analysed in two modes (positive and negative electrospray ionisation). Some substances are detected in both modes, others only in one of the modes. The number of features can therefore not be added.