Water quality of the Meuse watershed: Assessment using a multi-biomarker approach with caged three-spined stickleback (Gasterosteus aculeatus L.).

The use of a multi-biomarker approach with three-spined sticklebacks (Gasterosteus aculeatus) through an active biomonitoring strategy appears to be a promising tool in water quality assessment. The present work proposes to assess the efficiency of these tools in the discrimination of some sites in a large scale on the Meuse basin in Europe. The study was part of an EU program which aims to assess water quality in the Meuse across the French-Belgian border. Sticklebacks were caged 21 days upstream and downstream from the wastewater treatment plants (WWTPs) of Namur (Belgium), Charleville-Mézières (France), Bouillon (Belgium) and Avesnes-sur-Helpe (France). First, the state of a variety of physiological functions was assessed using a battery of biomarkers that represented innate immunity (leucocyte mortality and distribution, phagocytosis activity, respiratory burst), antioxidant system (GPx, CAT, SOD and total GSH content), oxidative damages to the membrane lipids (TBARS), biotransformation enzymes (EROD, GST), synaptic transmission (AChE) and reproduction system (spiggin and vitellogenin concentration). The impacts of the effluents were first analysed for each biomarker using a mixed model ANOVA followed by post-hoc analyses. Secondly, the global river contamination was assessed using a principal component analysis (PCA) followed by a hierarchical agglomerative clustering (HAC). The results highlighted a small number of effects of WWTP effluents on the physiological parameters in caged sticklebacks. Despite a significant effect of the "localisation" factor (upstream/downstream) in the mixed ANOVA for several biomarkers, post-hoc analyses revealed few differences between upstream and downstream of the WWTPs. Only a significant decrease of innate immune responses was observed downstream from the WWTPs of Avesnes-sur-Helpe and Namur. Other biomarker responses were not impacted by WWTP effluents. However, the multivariate analyses (PCA and HAC) of the biomarker responses helped to clearly discriminate the different study sites from the reference but also amongst themselves. Thus, a reduction of general condition (condition index and HSI) was observed in all groups of caged sticklebacks, associated with a weaker AChE activity in comparison with the reference population. A strong oxidative stress was highlighted in fish caged in the Meuse river at Charleville-Mézières whereas sticklebacks caged in the Meuse river at Namur exhibited weaker innate immune responses than others. Conversely, sticklebacks caged in the Helpe-Majeure river at Avesnes-sur-Helpe exhibited higher immune responses. Furthermore, weak defence capacities were recorded in fish caged in the Semois river at Bouillon. This experiment was the first to propose an active biomonitoring approach using three-spined stickleback to assess such varied environments. Low mortality and encouraging results in site discrimination support the use of this tool to assess the quality of a large number of water bodies.

Development of a multi-residue analysis of diclofenac and some transformation products in bivalves using QuEChERS extraction and liquid chromatography-tandem mass spectrometry. Application to samples from mesocosm studies.

Pharmaceuticals are ubiquitously present in the aquatic environment, mainly due to insufficient removal in wastewater treatment plants. Although these compounds are often found at trace levels in waters, long-term exposure can have negative impacts on biotic communities due to their inherent biological activity. The non-steroidal anti-inflammatory drug diclofenac (DCF) is one of the most frequently detected human pharmaceuticals in water and has recently been included in the "watch" list of the European Union. However little data are available on the detection of this substance and its transformation products in aquatic organisms. In this context, an analytical methodology has been developed to quantify traces of DCF along with its biotic and abiotic transformation products in a wild species of bivalve, the zebra mussel Dreissena polymorpha. A modified QuEChERS extraction was implemented on a small quantity of soft bivalve tissue (100mg). This was followed by liquid chromatography coupled to tandem-mass spectrometry (LC-MS/MS) with electrospray ionization in positive mode (ESI+). Whole analytical method was validated on spiked real samples, with regard to linearity (from 1 to 50 or 100ng/g depending on the target compounds, R(2)>0.99), intra-day precision (relative standard deviation (RSD)<18%), inter-day precision (RSD <25%), (recoveries 78-117%), and limits of detection and of quantification (both inferior or equal to 1ng/g). The optimized method was successfully applied to organisms collected from mesocosm experiments. Bioconcentration factors comprised between 4 and 13 were observed for DCF in the zebra mussels. To the best of our knowledge, the product 2-indolone was for the first time detected in bivalves, with levels up to 6ng/g.