Binnen het VMM waterbodemmeetnet wordt de waterbodemkwaliteit van 600 meetplaatsen in zowel bevaar-bare als onbevaarbare waterlopen aan de hand van de Triade methode opgevolgd. De kwaliteitsbeoordelingis gebaseerd op een combinatie van chemische, biologische en ecotoxicologische parameters. Daarnaast is ereen Vlaams palingpolluentenmeetnet dat wordt beheerd door het INBO. Dit meetnet beschikt momenteelover gegevens van ca 350 meetplaatsen op kanalen, rivieren en afgesloten watersystemen waar de concen-tratie van een reeks van PCB’s, zware metalen en pesticiden in paling opgevolgd wordt. Dit biedt ook demogelijkheid om de biobeschikbaarheid van deze vervuilende stoffen aan te tonen. Via afstemming kunnenbeide meetnetten een krachtiger beleidsinstrument betekenen voor de waterbodemsanering en het water-beleid in brede zin. Er wordt nader ingegaan op de praktische implicaties van deze samenwerking rekeninghoudend met de historiek, eigenheid en complementariteit van beide meetnetten.Within the sediment monitoring network from the Flemish Environmental Agency (VMM) the sedimentquality of 600 locations in Flanders in both navigable as well as in unnavigable waters, is monitored bymeans of the TRIADE method. This TRIADE sediment quality assessment is based on a combination ofchemical, biological and ecotoxicological parameters. The Research Institute for Nature and Forest (INBO)uses the Flemish eel pollutant monitoring network to monitor 350 locations in Flanders. These locations aresituated on canals, rivers and on closed water bodies. The concentrations of PCBs, heavy metals andorganochlorine pesticides are quantified in eel. At the same time these concentrations in eel give us valuableinformation on the bioavailability of these substances. Closer cooperation between both monitoring net-works will provide an efficient policy tool, specifically for the sanitation/decontamination of the sedimentand for the water policy in general. We will go into detail on the practical implications of such a kind ofcooperation keeping in account the history, singularity and complementarity of both monitoring networks.
The first fish-based index to assess the ecological quality of lowland rivers in Flanders (Belgium) is based on data obtained from different fishing techniques without considering the gear specificity. As a consequence, this index could not be intercalibrated with other European indices which concentrate on one gear type only. In order to comply with the European Water Framework Directive, we developed a new fish-based index using data obtained from surveys in rivers with electric gear only. All 293 selected rivers belonged to the bream or barbel zone. An updated reference list of fish species was compiled based on previous work and recent data. Abiotic data were collected according to standard methods and habitat quality of all surveyed sites was pre-classified using pressure indicators. To develop the new index candidate metrics were selected from the literature and metric values were calculated. Linear mixed regression models selected metrics based on their response to the pre-classified habitat status. Correlation tests were performed to avoid redundancy among responsive metrics. Boundaries for metric scores were defined based on the calculated metric values. The new index of biotic integrity (IBI) was calculated by summation of the metric scores, and transformed to an ecological quality ratio (EQR), ranging between 0 and 1. Five integrity classes, ranging from bad to maximal ecological potential, were attributed and compared to the pre-classified habitat status of the site. In addition, the new index was also validated with an independent set of data. The new IBI proved to successfully assess the ecological status of the rivers.
