60 research outputs found
Transcriptional analysis of rat piriform cortex following exposure to the organophosphonate anticholinesterase sarin and induction of seizures
Evaluation de la contamination en pesticides des tributaires du Bassin dâArcachon et dĂ©veloppement d'un Ă©chantillonneur passif spĂ©cifique des herbicides anioniques
From the early 2000s, the Arcachon Bay suffers from environmental crises that have led to the decline of the Zostera spp. meadows, and to the episodic mortality of oysters spats. Therefore, the toxic pressure (including pesticides) has been questioned, and several environmental monitoring programs have been established since 2005. The study presented in this manuscript is part of the research program OSQUAR (Oyster and environmental Quality, dynamic approach of the Arcachon Bay, 2010-2012), and focuses on continental pesticides inputs towards the lagoon. This new monitoring program consisted to expand the range of monitored compounds (including acidic herbicides), to use POCIS (Polar Organic Chemical Integrative Sampler) for the passive sampling of polar compounds, and to monitor continuously the main Arcachon Bay tributaries for nearly two years. Because of the inadequacy of POCIS (and other devices currently available), a monthly grab sampling strategy has been implemented for the monitoring of acidic herbicides, and a specific passive sampler has been developed in parallel. To do so, an analytical method has been first developed for these compounds, to meet the requirements of environmental monitoring (reduction of matrix effects, limits of quantification of few ng L-1). The highlighting of the predominance of the acidic metabolites of chloroacetanilides in the Arcachon Bay tributaries has been a major advance in the characterization of the toxic pressure, and pointed out, otherwise, the needs for a specific passive sampling tool for these contaminants. Therefore, several passive samplers have been developed, based on existing devices (POCIS and Diffusive Gradient in Thin-film). The integrative behaviour of the samplers has been first optimized by adapting the geometry (exposure surface area, and amount of receiving phase), or by changing the nature of the receiving phase. Then, the quantitative behaviour has been improved by adapting the PRC (performance and reference compound) approach, or using a diffusive gel.Le Bassin dâArcachon souffre depuis le dĂ©but des annĂ©es 2000 de crises environnementales qui ont engendrĂ© la rĂ©gression de lâherbier de zostĂšres et la mortalitĂ© Ă©pisodique des naissains dâhuĂźtres. DĂšs lors, la pression toxique et notamment phytosanitaire a Ă©tĂ© mise en cause et a fait lâobjet de plusieurs suivis environnementaux dans la lagune et ses principaux tributaires depuis 2005. LâĂ©tude prĂ©sentĂ©e dans ce manuscrit sâinscrit dans le programme de recherche OSQUAR (OstrĂ©iculture et QualitĂ© du milieu, approche dynamique du bassin dâArcachon, 2010-2012), et porte sur le suivi des apports en pesticides vers le Bassin dâArcachon par les eaux continentales. La plus-value de cette nouvelle Ă©tude rĂ©side dans lâĂ©largissement du panel de molĂ©cules suivies, notamment avec la prise en compte des composĂ©s acides ; dans lâutilisation dâĂ©chantillonneurs passifs de type POCIS (Polar Organic Chemical Integrative Sampler) pour lâĂ©chantillonnage et la prĂ©concentration in situ des composĂ©s hydrophiles (intĂ©gration en continu des Ă©pisodes de contamination) ; et dans lâacquisition dâune chronique pendant prĂšs de deux ans. Du fait de lâinadĂ©quation du POCIS (et des autres Ă©chantillonneurs passifs aquatiques disponibles actuellement), une stratĂ©gie dâĂ©chantillonnage ponctuel mensuel a Ă©tĂ© mise en place pour le suivi environnemental des herbicides organiques acides, et un Ă©chantillonneur passif spĂ©cifique de ces composĂ©s a Ă©tĂ© dĂ©veloppĂ© en parallĂšle. Pour ce faire, une mĂ©thode analytique spĂ©cifique des substances acides a Ă©tĂ© dĂ©veloppĂ©e dans un premier temps, notamment pour rĂ©pondre aux exigences liĂ©es aux suivis environnementaux (rĂ©duction des effets de matrice, limites de quantification de lâordre du ng.L-1). La mise en Ă©vidence par la suite de la prĂ©dominance des mĂ©tabolites acides des chloroacĂ©tanilides dans la contamination des tributaires du Bassin dâArcachon a constituĂ© une avancĂ©e majeure dans la caractĂ©risation de la pression toxique du milieu, et a par ailleurs montrĂ© les besoins en matiĂšre dâĂ©chantillonnage passif pour ce type de contaminants. Par consĂ©quent, des outils adaptĂ©s Ă leur Ă©chantillonnage ont Ă©tĂ© dĂ©veloppĂ©s, en se basant sur des dispositifs prĂ©existants (POCIS et Diffusive Gradient in Thin-film). Le caractĂšre intĂ©gratif de lâĂ©chantillonneur a Ă©tĂ© optimisĂ© soit en adaptant la gĂ©omĂ©trie, soit en modifiant la nature de la phase rĂ©ceptrice. Ensuite, lâaspect quantitatif des dispositifs a Ă©tĂ© amĂ©liorĂ© en adaptant lâapproche PRC (composĂ© de performance et de rĂ©fĂ©rence), ou bien en utilisant un gel diffusif
Suivi de la contamination des tributaires du Bassin d'Arcachon par les pesticides et tests écotoxicologiques sur diatomées
[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCAInternational audienceThe Arcachon bay actually shows some signs of dysfunction which may lead to suspicion of effects of anthropogenic alterations from various types (trophic, toxic ...). An integrated study was then started, part of which relates to the diagnosis of pollution from mainland via input from coastal tributaries. One objective is to characterize the pesticide pollution coming from the 9 major tributaries. Neutral and sufficiently hydrophilic pesticides (ie 1L'Ă©chantillonnage passif des substances organiques de synthĂšse suscite un intĂ©rĂȘt croissant depuis son apparition par son gain de reprĂ©sentativitĂ© temporelle, sa facilitĂ© de mise en Âœuvre et son coĂ»t acceptable. Depuis le dĂ©but des annĂ©es 1990, plusieurs dispositifs ont Ă©tĂ© dĂ©veloppĂ©s pour Ă©chantillonner diffĂ©rents types de contaminants. Le Polar Organic Chemical Integrative Sampler (POCIS) est l'outil le plus adaptĂ© Ă l'Ă©chantillonnage des pesticides pour diffĂ©rentes applications (e.g. monitoring ; appui Ă l'Ă©cotoxicologie), en particulier grĂące Ă l'utilisation d'un composĂ© de performance et de rĂ©fĂ©rence (PRC). L'objectif de cette Ă©tude est de caractĂ©riser la pollution Ă pesticides dans neuf des principaux tributaires du Bassin d'Arcachon. Des POCIS ont Ă©tĂ© dĂ©ployĂ©s pour l'Ă©chantillonnage des pesticides neutres (i.e.
Etalonnage des échantillonneurs passifs du type POCIS pour les pesticides polaires : essai d'intercomparaison et recommandations pour l'harmonisation des données d'étalonnage en laboratoire
La perspective dâapplication des Ă©chantillonneurs passifs dans le cadre de la DCE nĂ©cessite au prĂ©alable lâĂ©tablissement de donnĂ©es dâĂ©talonnage fiables. Or, concernant des dispositifs tels que les Polar Organic Chemical Integrative Samplers (POCIS), a priori adaptĂ©s pour lâĂ©chantillonnage des pesticides organiques polaires, ces donnĂ©es sont encore peu renseignĂ©es et/ou trĂšs hĂ©tĂ©rogĂšnes ou alors dĂ©terminĂ©es via des systĂšmes expĂ©rimentaux en laboratoire certes contrĂŽlĂ©es mais aussi trĂšs variables. DâaprĂšs lâĂ©tude de la littĂ©rature Ă ce sujet, Ă dĂ©faut de disposer de valeurs de rĂ©fĂ©rence, il ressort un besoin dâharmonisation des constantes cinĂ©tiques (ou encore des taux dâĂ©chantillonnage) et de recommandations quant Ă la maniĂšre de les acquĂ©rir. Ainsi, il a Ă©tĂ© menĂ© un essai dâintercomparaison portant sur lâĂ©talonnage dâune liste commune dâherbicides polaires (acĂ©tochlore, alachlore, atrazine, diuron et linuron) au sein de trois laboratoires experts dans le domaine de lâĂ©chantillonnage passif et membre du consortium Aquaref. Le second objectif de ce travail a visĂ© lâĂ©tude de lâinfluence des conditions expĂ©rimentales et des systĂšmes utilisĂ©s pour l'Ă©talonnage, Ă savoir le systĂšme employĂ©, le niveau de dopage des eaux en pesticides, lâagitation du milieu ou encore la tempĂ©rature, ce qui a permis dâapprĂ©hender la robustesse des donnĂ©es associĂ©e Ă la phase dâĂ©talonnage en laboratoire. Les donnĂ©es dâĂ©chantillonnage obtenues dans les diffĂ©rents laboratoires impliquĂ©s Ă©tant comparables pour les molĂ©cules « communes » aux diffĂ©rents essais, lâagrĂ©gation des donnĂ©es des diffĂ©rents laboratoire a Ă©tĂ© rĂ©alisĂ©e pour fournir lâintĂ©gralitĂ© des donnĂ©es de taux dâĂ©chantillonnage acquises Ă ce jour
Optimization of the polar organic chemical integrative sampler for the sampling of acidic and polar herbicides
International audienceThis paper presents an optimization of the pharmaceutical Polar Organic Chemical Integrative Sampler (POCIS- 200) under controlled laboratory conditions for the sampling of acidic (2,4-dichlorophenoxyacetic acid (2,4-D), acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid, bentazon, dicamba, mesotrione, and metsulfuron) and polar (atrazine, diuron, and desisopropylatrazine) herbicides in water. Indeed, the conventional configuration of the POCIS-200 (46 cm2 exposure window, 200 mg of OasisÂź hydrophilic lipophilic balance (HLB) receiving phase) is not appropriate for the sampling of very polar and acidic compounds because they rapidly reach a thermodynamic equilibrium with the Oasis HLB receiving phase
Use of Mixed-Mode Ion Exchange Sorbent for the Passive Sampling of Organic Acids by Polar Organic Chemical Integrative Sampler (POCIS)
International audienceAcidic herbicides are increasingly monitored in freshwater, since their high solubility favors their rapid transfer to the water phase. Therefore, contaminant levels in the water can vary rapidly and passive sampling would be preferred over spot sampling to integrate all pollution events over a given exposure time. In this work, we propose to compare the conventional pharmaceutical polar organic chemical integrative sampler (POCIS) with modified POCISs containing two different receiving phases: a standard polystyrene divinylbenzene polymer with a higher specific surface area (Chromabond HR-X) and a mixed-mode anion exchange sorbent providing additional strong anion exchange interaction sites (Oasis MAX). Due to its hydrophobic character, Chromabond HR-X had little interaction with water (no sampling of acidic herbicides); whereas Oasis MAX provided acceptable sampling parameters (longer kinetic regime together with higher sampling rates). Additional experiments with POCIS-MAX showed no influence of nitrates on analyte uptakes, and linear isotherms reaching 10 ÎŒg Lâ1, supporting the applicability of this device for the sampling of organic acids in continental water. The performance and reference compound (PRC) approach would be then applicable for POCIS-MAX if no competition is observed with other anions, especially organic acids (e.g., humic acids)
Hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry for acidic herbicides and metabolites analysis in fresh water
International audienceTheoretical papers and environmental applications of hydrophilic interaction liquid chromatography (HILIC) have been published for a wide range of analytes, but to our knowledge, no study focused on acidic herbicides (e.g., triketones, phenoxy acids, sulfonylurea, and acidic metabolites of chloroacetanilides). Matrix effects are the main obstacle to natural sample analysis by liquid chromatography coupled with tandem mass spectrometry (MS) via an electrospray ionization (ESI) interface. Therefore, we paid particular attention on limiting interference by (i) adapting the emerging HILIC technique, which is generally considered more sensitive than conventional reversed phase liquid chromatography and (ii) optimizing the solid phase extraction (SPE) step using a design of experiment. A rapid and reliable off line SPE-HILIC-ESI-MS/MS method was thus developed for the quantification of acidic herbicides in fresh water, with limits of quantifications (LOQs) ranging from 5 to 22 ng l1 . Then, the analysis of freshwater samples highlighted the robustness of the method, and the importance of the chloroacetanilides metabolites among the studied analytes
Brain Metabolic Disorders Induced by Convulsive Dose of Soman. In vivo Study Using Chemical Shift Imaging NMR Spectroscopy in Mice
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Impact of manganese on the hippocampus metabolism in the context of MEMRI: a proton HRMAS MRS study
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Ăvaluation expĂ©rimentale de l'effet de la tempĂ©rature et de la vitesse d'Ă©coulement sur l'absorption des pesticides par le POCIS et proposition d'un modĂšle pour la prĂ©diction du taux d'Ă©chantillonnage
International audienceVarious studies have dealt with the effects of physico-chemical parameters (temperature, pH, organic matter content, salinity) or physical parameters (flow velocity and temperature) under laboratory conditions for sampling of hydrophilic (pharmaceuticals and pesticides) chemicals. These studies have demonstrated i) variable influence of these parameters on sampling rates ii) some consecutive bias on the calculated time weighted average concentrations (TWAC). However, all of these factors were studied individually, and possible interactions were not addressed. The first part of our work was dedicated to the calibration of POCIS with various temperatures (10 and 25°C) and flow velocities (from 0.7-1 cm.s-1 to 44-45 cm.s-1). Principal effects, and possible interactions between the two parameters, on sampling rates (Rs) were investigated with a full factorial design of experiment. The results showed a predominant impact of the flow velocity on Rs for 10 moderately polar pesticides (log Kow=2.18-4.14). Conversely, the temperature seemed to have only secondary and low influence on Rs variations. The second part consisted in a compilation of Rs data for the 10 analytes calibrated during this study, and also reported in the literature. Knowing the exchanging surface area A for POCIS, the global resistance to the mass transfer coefficients 1/ko were determined from these Rs (with 1/ko=A/Rs), and then plotted against the experimental bulk flow velocity values reported. The fitting of a non-linear model based on the dimensionless Sherwood number provided useful estimates of regression coefficients, for a possible prediction of Rs under various flowing conditions. For instance, the results obtained in the case of atrazine (1/ko ranging from 0.054±0.003 and 0.132±0.027 d.cm-1, depending on flow velocity) were in good agreement with the 1/ko values estimated by Booij et al. 2017. Some correlations were also observed between the flow velocity and the desorption rate of DIA-d5 (from 0.023 to 0.154 d-1). Such an observation could be a promising way to take into account the DBL thickness contribution, according to the hydrodynamic conditions, and then a likely improvement of the accuracy for in situ TWAC estimates
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