La Directive Cadre sur l'Eau (DCE) (2000/60) a mis en place une liste de 33 substances prioritaires, avec des normes qualité de l'environnement (NQE) pour chaque substance, et leur concentration dans les milieux aquatiques qui ne doivent pas dépasser c es NQE. De plus, elle exige des performances analytiques spécifiques pour ces méthodes: la limite de quantification doit être au moins aussi basse que 30% des NQE et l'incertitude de la méthode au niveau de la NQE doit être inférieure à 50%, pour k = 2. Par conséquent, le défi analytique actuel est de mesurer de faibles concentrations de ces polluants dans les matrices parfois difficiles. Ceci peut être réalisé en améliorant la technique d'extraction utilisée pour obtenir un extrait de l'échantillon plus concentré et plus propre. Dans ce contexte, les trois méthodes d'analyse ont été mises au point pour déterminer les composés musqués, alkylphénoliques et organométalliques dans les matrices environnementales. Ces techniques d'extraction et de pré-concentration innovantes ont ensuite été appliquées pour l’évaluation de la présence de ces composés dans les stations d'épuration locales et dans les cours d'eau récepteurs. Enfin, les niveaux de concentrations de fond au niveau national ont été mises à jour pour les composés organométalliques. / The ambitious Water Framework Directive (WFD) (2000/60) set up a list of 33 priority substances, with Environmental Quality Standards (EQS) for each substance, and their concentration in aquatic environments should not go beyond the EQS. Additionally, it requires specific analytical method performances: the limit of quantification must be at least as low as 30 % of the EQS and the uncertainty of the method at the EQS level must be inferior to 50 %, for k=2. Therefore, the current analytical challenge is to measure low concentrations of these pollutants in sometimes difficult matrices. This can be achieved by improving the extraction technique used to obtain a more concentrated and cleaner sample extract. In this context, 3 analytical methods were developed to determine musk, alkylphenols and organometallic compounds in environmental matrices. Recent extraction and pre-concentration techniques were applied and later the occurrence of these compounds in the local WWTPs and in the receiving water bodies where they are discharged was evaluated. Additionally, updated French background concentrations were established for organometallic compounds.

Indiana University-Purdue University Indianapolis (IUPUI) / Methylmercury (MeHg) exposure from occupational, environmental and food sources is a significant threat to public health. MeHg poisonings in adults may result in severe psychological and neurological deficits, and in utero exposures can confer significant damage to the developing brain and impair neurobehavioral and intellectual development. Recent epidemiological and vertebrate studies suggest that MeHg exposure may contribute to dopamine (DA) neuron vulnerability and the propensity to develop Parkinson’s disease (PD). I have developed a novel Caenorhabditis elegans (C. elegans) model of MeHg toxicity and have shown that low, chronic exposure confers embryonic defects, developmental delays, reduction in brood size, decreased animal viability and DA neuron degeneration. Toxicant exposure results in an increase in reactive oxygen species (ROS) and the robust induction of several glutathione-S-transferases (GSTs) that are largely dependent on the PD-associated phase II antioxidant transcription factor SKN-1/Nrf2. I have also shown that SKN-1 is expressed in the DA neurons, and a reduction in SKN-1 gene expression increases MeHg-induced animal vulnerability and DA neuron degeneration. Furthermore, I incorporated a novel genome wide reverse genetic screen that identified 92 genes involved in inhibiting MeHg-induced animal death. The putative multidrug resistance protein MRP-7 was identified in the screen. I have shown that this transporter is likely expressed in DA neurons, and reduced gene expression increases cellular Hg accumulation and MeHg-associated DA neurodegeneration. My studies indicate that C. elegans is a useful genetic model to explore the molecular basis of MeHg-associated DA neurodegeneration, and may identify novel therapeutic targets to address this highly relevant health issue.