Context and project
To meet the obligations of the framework directive on water and its daughter directives, Member States are required to evaluate the chemical state of bodies of surface water. In this context, some environment quality standards (EQS) have been set regarding biota (fish, invertebrate) and the revision of the EQS directive has led to an increase in the number of these biota EQS (directive 2013/39/EU). Faced with uncertainties related to the use of these organisms in monitoring (variations related to age, species, gender, time in the body of water, metabolism, absence of the biota in certain bodies of water, etc.), some Member States also advocate the use of passive samplers whose deployment is easier to manage (exposure time, fixed location, exposed surface, etc.). They allow for low-cost sampling, the detection and quantification of compounds at ultra-trace levels, and the comparison of data from different stations. The new EQS directive also encourages the continuation of their development.
The Moerman “biota” project began in 2013 with the main aim being to develop the monitoring of bodies of surface water relating to “biota” and to develop, evaluate and validate the use of passive samplers as a possible alternative to the “biota” matrix. In addition, an element devoted to developing invertebrate caging techniques is also expected in the context of this project. Caging may constitute an alternative method to the sampling of organisms, particularly in terms of sites where the species in question are absent.
During the project’s first year, the most relevant biota species were selected and a sampling strategy developed. Four fish species and aquatic invertebrate (crustaceans and molluscs) were selected for the analysis of micro pollutants. The contaminants targeted are mercury, hexachlorobenzene and polycyclic aromatic hydrocarbons (benzo-a-pyrene and fluoranthene), substances for which an EQS is available in the “biota” matrix.
The development of analyses for this specific matrix is currently underway. In 2013, samples were taken from various stations, mainly chosen from within the DCE monitoring network in the Walloon region in order to obtain sufficient sampling to allow for these developments. Sampling is carried out in collaboration with the DEMNA during annual fish surveys and with Liège University. In fact, an agreement with the Walloon region, prepared in the form of a Service Level Agreement (SLA) concerns the terms of collaboration between the ISSep, the DGO3, including the DEMNA, and the results obtained. In addition, a partnership agreement with the ULg for the performance of additional fishing has been signed.
However, the experimental phase relating to active biomonitoring is currently being developed before practical experience is gathered. The latter concerns the choice of organism to be caged (initially, the caging of Gammarus pulex will be planned), the choice of cage type, caging sites (reference site(s) and polluted sites for performing tests), the acclimatisation system for organisms in the laboratory as well as a number of additional methods such as the size of organisms, the quantity of organisms per cage, the number of cages per site, the food required, optimal physico-chemical parameters, etc. The development of caging methods is planned for 2014.
In this context, a European drafting group intended to implement the biota monitoring programmes has been organised; the ISSeP is part of this group. The processing and expression of the resulting data with a view to assessing its compliance relative to environmental quality standards in biota are also discussed. The publication of the final version of this “Supplementary guidance for the implementation of EQSbiota” was planned for September 2014. A first meeting was organised in London in 2013 to organise the drafting. Two additional meetings intended to monitor the drafting will be organised in January 2014 in Paris and in May 2014 in Amsterdam. A contribution will be made through the drafting of the chapter concerning the best caging practices for aquatic organisms.
Finally, a bibliographic study is currently underway to determine which types of passive samplers could be used for this project.