Adsorption des perturbateurs endocriniens lors de la potabilisation : Développement d'une méthodologie d'obtention des paramètres d'équilibre et cinétiques

Endocrine disrupting compounds are micropollutants that have shown estrogenic activity at environmentally relevant concentration levels, from µg. L-1 to ng. L-1. Activated carbon adsorption is specifically designed to remove organic pollution. The assessment of the process efficiency in real conditions (low concentration level, simultaneous adsorption of organic matter) requires stringent and costly experimentations, in particular due to the analysis. An analytical method involving SPE-UPLC-MS/MS was optimized and validated. Experimental data has been analysed and processed using an advanced statistical treatment in order to assess the influence of the heteroskedasticity of the signal’s variance on the precision of the results. A methodology was developed for the determination of the adsorption capabilities based on high concentration adsorption experiments and downward extrapolation of the adsorption performance at low concentration level using modelling. Bisphenol A and ethynylestradiol, and two powdered activated carbons were used for experiments at high concentration level and, for validation purpose, at low concentration level. Several models have been tested in order to determine their extrapolation capabilities. Results have shown that the IAST model, for competitive adsorption, and the HSDM theory, for kinetics, fitted at high concentration level are capable of downward extrapolation of adsorption equilibriums and kinetics of both target compounds at low concentration level.Les perturbateurs endocriniens sont des micropolluants qui ont révélé un potentiel estrogénique à des teneurs retrouvées dans les eaux, allant du µg. L-1 au ng. L-1. L’adsorption sur charbon actif est le procédé de traitement spécifiquement conçu pour l’élimination de la pollution organique. L’évaluation des performances de ce procédé dans des conditions réelles (faibles concentrations de produit, présence de matière organique) nécessite des essais lourds et onéreux, notamment vis-à-vis de l’analyse. Une méthode d’analyse par SPE-UPLC-MS/MS a été mise en place et validée. Un traitement statistique poussé a été effectué pour déterminer l’impact de l’hétéroscédasticité de la variance du signal du spectromètre de masse sur la précision des résultats. Une méthodologie a été développée devant permettre d’obtenir ces informations en effectuant des essais d’adsorption à haute concentration puis en extrapolant les performances d’adsorption à basse concentration à l’aide de modèles. Les essais ont été effectués sur le bisphénol A et l’éthinylestradiol et deux charbons actifs en poudre, à haute et, pour la validation, à basse concentration. Différents modèles ont été testés afin d’évaluer leur capacité d’extrapolation. Les résultats ont montré que l’approche de l’IAST, pour l’adsorption compétitive, et le modèle HSDM, pour la cinétique, calibrés à haute concentration sont capables d’extrapoler les équilibres et cinétiques des composés étudiés à basse concentration

Adsorption des perturbateurs endocriniens lors de la potabilisation (développement d une méthodologie d obtention des paramètres d équilibre et cinétiques)

Les perturbateurs endocriniens sont des micropolluants qui ont révélé un potentiel estrogénique à des teneurs retrouvées dans les eaux, allant du g.L-1 au ng.L-1. L adsorption sur charbon actif est le procédé de traitement spécifiquement conçu pour l élimination de la pollution organique. L évaluation des performances de ce procédé dans des conditions réelles (faibles concentrations de produit, présence de matière organique) nécessite des essais lourds et onéreux, notamment vis-à-vis de l analyse. Une méthode d analyse par SPE-UPLC-MS/MS a été mise en place et validée. Un traitement statistique poussé a été effectué pour déterminer l impact de l hétéroscédasticité de la variance du signal du spectromètre de masse sur la précision des résultats. Une méthodologie a été développée devant permettre d obtenir ces informations en effectuant des essais d adsorption à haute concentration puis en extrapolant les performances d adsorption à basse concentration à l aide de modèles. Les essais ont été effectués sur le bisphénol A et l éthinylestradiol et deux charbons actifs en poudre, à haute et, pour la validation, à basse concentration. Différents modèles ont été testés afin d évaluer leur capacité d extrapolation. Les résultats ont montré que l approche de l IAST, pour l adsorption compétitive, et le modèle HSDM, pour la cinétique, calibrés à haute concentration sont capables d extrapoler les équilibres et cinétiques des composés étudiés à basse concentration.Endocrine disrupting compounds are micropollutants that have shown estrogenic activity at environmentally relevant concentration levels, from g.L-1 to ng.L-1. Activated carbon adsorption is specifically designed to remove organic pollution. The assessment of the process efficiency in real conditions (low concentration level, simultaneous adsorption of organic matter) requires stringent and costly experimentations, in particular due to the analysis. An analytical method involving SPE-UPLC-MS/MS was optimized and validated. Experimental data has been analysed and processed using an advanced statistical treatment in order to assess the influence of the heteroskedasticity of the signal s variance on the precision of the results. A methodology was developed for the determination of the adsorption capabilities based on high concentration adsorption experiments and downward extrapolation of the adsorption performance at low concentration level using modelling. Bisphenol A and ethynylestradiol, and two powdered activated carbons were used for experiments at high concentration level and, for validation purpose, at low concentration level. Several models have been tested in order to determine their extrapolation capabilities. Results have shown that the IAST model, for competitive adsorption, and the HSDM theory, for kinetics, fitted at high concentration level are capable of downward extrapolation of adsorption equilibriums and kinetics of both target compounds at low concentration level.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Bilan des différentes approches mises en œuvre lors de l’expertise sur les données bancarisées et propositions d’harmonisation

L’amélioration continue de la qualité des données de la surveillance a pour objectif de rendre plus fiables et mieux documentées les données produites dans le cadre de la surveillance des milieux aquatiques. Ces données sont bancarisées dans des bases de données nationales (ADES pour les eaux souterraines, QUADRIGE pour le milieu marin, Naïades pour les eaux de surface) ou propres à chaque Agence ou Office de l’eau. Maîtriser la qualité de la donnée, notamment au travers des métadonnées associées, permet à la fois de faciliter leur exploitation dans le cadre d’expertises et/ou des évaluations de l’état des masses d’eau, mais aussi de mieux les comparer dans l’espace et le temps.   Depuis 2011, différentes études ont été conduites dans le cadre des programmes Aquaref, pour i) vérifier la complétude des données et identifier les erreurs de codification SANDRE ii) évaluer l’évolution des performances des méthodes analytiques employées et leur conformité au regard des exigences réglementaires (Ghestem, 2012 ; Guigues 2012), iii) identifier d’éventuels effets laboratoires (Bristeau et Ghestem, 2013, 2015 et 2016 ; Ngo et Botta, 2016) ou encore iv) estimer les incertitudes de mesure à partir de séries chronologiques (Soudant et al., 2015 et 2017).   Au travers de ces études, le constat a été fait que l’une des questions premières qui se pose lors de l’exploitation des données bancarisées concerne la manière de prendre en compte les données dites « censurées », c’est-à-dire les données inférieures à une limite (détection ou quantification par exemple). De plus, compte tenu des évolutions des exigences réglementaires et des performances des moyens de mesure, il est très courant d’avoir à exploiter des séries de données caractérisées par des limites de détection ou quantification différentes. Un autre point qu’il est important d’adresser est le choix des  descripteurs statistiques (comme la moyenne, la médiane etc.) à estimer ainsi que le type d’approche en lien avec la distribution des données (par exemple paramétrique pour les données distribuées selon une loi normale, ou non paramétrique dans les autres cas) et les tests statistiques à mettre en oeuvre. Ces différents choix sont en général très dépendants du jeu de données (nombre, distribution etc.).   Les objectifs de cette note sont, dans un premier temps, de présenter les différentes études réalisées dans le cadre du programme Aquaref entre 2011 et 2018, dans un deuxième temps, de décrire les approches existantes avec leurs inconvénients et leurs avantages pour répondre notamment à la question des données censurées et des approches statistiques les mieux adaptées à mettre en oeuvre. Enfin dans un troisième temps des propositions et recommandations sont formulées pour améliorer l’exploitation des données bancarisées

Prediction of the accumulation behavior of pesticides in PDMS-coated stir bars used as passive samplers in freshwaters

International audiencePassive samplers accumulate organic contaminants at rates that depend on in-field exposure conditions such as freshwater flow velocity, water temperature and water quality. Time-weighted average concentrations can be determined by using a correction process such as the performance reference compound (PRC) method. This study presented a new approach to predict the accumulation behavior of pesticides in polydimethylsiloxane-coated stir bars under different exposure conditions and assign a specific PRC to each pesticide for quantitative purposes. We used an experimental design with eight simultaneous accumulation kinetics of 13 pesticides and elimination kinetics of three PRC candidates run in a flow-through system to determine the effects of flow velocity, water temperature and dissolved organic matter on the kinetic constants. We identified the parameters that had a significant effect on the accumulation of each pesticide and assigned a PRC candidate to each pesticide. We then used a discriminant function analysis to find the parameters that had a significant effect on accumulation of the 13 pesticides via their physical-chemical properties and to predict through a stochastic approach the parameters for seven other pesticides. This approach provides a better framework for identifying a PRC than conventional methods to determine unbiased concentrations in future monitoring efforts

A multi-family offline SPE LC-MS/MS analytical method for anionic, cationic and non-ionic surfactants quantification in surface water

International audienceOf the large number of emerging pollutants discharged from wastewaters into surface waters, surfactants are among those with the highest concentrations. However, few monitoring in river waters of these substances have already been performed and only on a few families, mostly anionic.This work aimed to develop a multi-family analytical strategy suitable for the quantification of low concentrations of surfactant in surface waters. Twelve families of surfactants, anionic, cationic and non-ionic were selected. Their quantification by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and their extraction by SPE were optimized by comparing different retention mechanisms. The best performances were obtained with a C18 grafted silica LC column and a hydrophilic-lipophilic balanced (HLB) polymeric SPE cartridge.The final analytical method was validated and applied for the quantification of surfactants in 36 river water samples. Method limits of quantification (LQ), intra and inter days precision and trueness were evaluated. With LQ between 15 and 485 ng/L, and trueness over 80%, this method was suitable for monitoring surfactants in surface water. Application on French river water samples revealed the presence of anionic, cationic and non-ionic surfactants with median concentrations from 24 ng/L for octylphenol ethoxylates (OPEO), up to 4.6 μg/L regarding linear alkylbenzene sulfonates (LAS)

Per- and polyfluoroalkyl substances (PFAS) in surface sediments: Occurrence, patterns, spatial distribution and contribution of unattributed precursors in French aquatic environments

International audienceWhile perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) are ubiquitous in aquatic environments, non-targeted methods have recently revealed the presence of numerous unidentified per- and polyfluoroalkyl substances (PFAS). Besides those methods, the total oxidizable precursor (TOP) assay has proved useful to estimate the contribution of unattributed perfluoroalkyl acids precursors (pre-PFAAs). In this study, an optimized extraction method was developed to examine the spatial distribution of 36 targeted PFAS in surface sediments collected at French nationwide scale (n = 43), including neutral, anionic and zwitterionic molecules. In addition, a TOP assay procedure was implemented to estimate the contribution of unattributed pre-PFAAs in these samples. Conversion yields of targeted pre-PFAAs were determined for the first time under realistic conditions and led to differences in oxidation profiles compared to the common spiked ultra-pure water method. PFAS were detected in 86 % of samples and ∑PFAStargeted was in the range < Limit of Detection – 23 ng g−1 dry weight (dw) (median: 1.3 ng g−1 dw), with ∑pre-PFAAstargeted representing on average 29 ± 26 % of ∑PFAS. Among pre-PFAAs, compounds of emerging interest such as the fluorotelomer sulfonamidoalkyl betaines 6:2 FTAB and 8:2 FTAB were respectively detected in 38 % and 24 % of samples, with levels similar to those of L-PFOS (<0.36–2.2, <0.50–6.8 and < 0.08–5.1 ng g−1 dw, respectively). A hierarchical cluster analysis coupled with a geographic information system-based approach revealed similarities between groups of sampling sites. For instance, elevated contribution of FTABs were associated with the proximity to airport activities where betaine-based aqueous film-forming foam (AFFFs) might have been used. In addition, unattributed pre-PFAAs were strongly correlated with ∑PFAStargeted and they accounted for 58 % of ∑PFAS (median value); they were generally found in larger quantity near industrial and urban areas where the highest ∑PFAStargeted were also observed

Per- and polyfluoroalkyl substances (PFAS) in surface sediments: Occurrence, patterns, spatial distribution and contribution of unattributed precursors in French aquatic environments

International audienceWhile perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) are ubiquitous in aquatic environments, non-targeted methods have recently revealed the presence of numerous unidentified per- and polyfluoroalkyl substances (PFAS). Besides those methods, the total oxidizable precursor (TOP) assay has proved useful to estimate the contribution of unattributed perfluoroalkyl acids precursors (pre-PFAAs). In this study, an optimized extraction method was developed to examine the spatial distribution of 36 targeted PFAS in surface sediments collected at French nationwide scale (n = 43), including neutral, anionic and zwitterionic molecules. In addition, a TOP assay procedure was implemented to estimate the contribution of unattributed pre-PFAAs in these samples. Conversion yields of targeted pre-PFAAs were determined for the first time under realistic conditions and led to differences in oxidation profiles compared to the common spiked ultra-pure water method. PFAS were detected in 86 % of samples and ∑PFAStargeted was in the range < Limit of Detection – 23 ng g−1 dry weight (dw) (median: 1.3 ng g−1 dw), with ∑pre-PFAAstargeted representing on average 29 ± 26 % of ∑PFAS. Among pre-PFAAs, compounds of emerging interest such as the fluorotelomer sulfonamidoalkyl betaines 6:2 FTAB and 8:2 FTAB were respectively detected in 38 % and 24 % of samples, with levels similar to those of L-PFOS (<0.36–2.2, <0.50–6.8 and < 0.08–5.1 ng g−1 dw, respectively). A hierarchical cluster analysis coupled with a geographic information system-based approach revealed similarities between groups of sampling sites. For instance, elevated contribution of FTABs were associated with the proximity to airport activities where betaine-based aqueous film-forming foam (AFFFs) might have been used. In addition, unattributed pre-PFAAs were strongly correlated with ∑PFAStargeted and they accounted for 58 % of ∑PFAS (median value); they were generally found in larger quantity near industrial and urban areas where the highest ∑PFAStargeted were also observed

Per- and Polyfluoroalkyl Substances (PFAS) in Surface Sediments: Occurrence, Patterns, Non-Physical Drivers and Contribution of Unidentified Precursors in French Aquatic Environments

International audienceSediment acts as a sink for per- and polyfluoroalkyl substances (PFAS), especially for perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs). Recently, non-targeted methods have shown the presence of numerous unknown PFAS in environmental samples. The contribution of these PFAS can be estimated by the Total Oxidisable Precursor assay (TOP), an oxidative method used to convert polyfluoroalkyl precursors (pre-PFAAs) into perfluoroalkyl acids (PFAAs). While sediment properties (grain size and organic carbon fraction, foc) were reported as controlling factors for some PFAS, the influence of non-physico-chemical drivers (e.g. population density) still needs to be investigated. Thus, this work focused on sediments from France and used optimized analytical methods and geographical information system (GIS) to fill these knowledge gaps. Extraction solvent was modified from methanol (MeOH) + ammonium hydroxide to MeOH + ammonium acetate for the analysis of 16 PFAAs, 6 alternative PFAAs and 14 pre-PFAAs covering anionic, neutral and zwitterionic species (n:2 fluorotelomer sulfonamidoalkyl betaines, n:2 FTABs). The optimized method exhibited suitable performances for its application on sediments (n=50) collected in 2018. The TOP assay was adapted to this specific method extraction. Perfluorododecanic acid,perfluorooctane sulfonic acid (PFOS) as well as perfluorooctanoic acid (PFOA) were often detected (76, 74 and 68 % respectively). 6:2 FTAB, 8:2 FTAB and perfluoropentyl propanoic acid (FPePA) were also detected (38, 26 and 36 %, respectively). Median ∑PFAS was 1.3 ng.g-1 dry weight (dw) (range < LOD–23 ng.g-1 dw). 6:2 FTAB and 8:2 FTAB levels ranged from < 0.36 to 6.4 ng.g-1 dw and < 0.50 to 7.4 ng.g-1 dw, which is in the same order of magnitude than L-PFOS (< 0.08–5.1 ng.g-1 dw) advocating for the necessity to include these PFAS in targeted analysis. At nationwide scale, PFOS and ∑PFCAs accounted for 37 ± 25% and 31 ± 21% of ∑PFAS, respectively, while targeted pre-PFAAs accounted for 29 ± 27%, thereby supporting the importance of the latter in sediment and the potential contribution of untargeted pre-PFAAs monitored by the TOP assay (data under acquisition). Correlations between PFAS levels normalized by foc, unidentified pre-PFAAs and non-physico-chemical drivers with GIS are being investigated. Preliminary results showed that PFAS levels were not correlated with sample site position in the hydrographic system (proxy: Strahler number)

Ultrasound-assisted sample preparation for simultaneous extraction of anionic, cationic and non-ionic surfactants in sediment

International audienceDespite their very wide use in various fields, knowledge concerning surfactants in environmental solid matrices is generally poor. One of the difficulties encountered in the analysis of surfactants is their very diverse physicochemical properties which require different extraction techniques.The objective of this work was therefore to develop an extraction method in sediments that allows the simultaneous analysis of anionic, cationic and non-ionic surfactants. Different extraction techniques (salting-out, ultrasound), solvents and additives were compared. The optimized method, followed by analysis by coupling liquid chromatography with tandem mass spectrometry, was then validated and applied to real samples in which the analytes were quantified by matrix matched calibration.Optimization of the extraction parameters showed different trends depending on the surfactant family. However, ultrasound assisted extraction with a 90/10 acetonitrile/water mixture at 1% acetic acid and 0.1 M EDTA showed the best results overall. The quantification limits obtained, between 6.4 μg/kg for linear alkylbenzene sulfonate (LAS) C10 and 158 μg/kg for 1-laureth sulfate, allow the analysis of traces in sediments. Eighteen of the 27 targeted surfactants were thus detected. The highest concentrations were found for LAS and quaternary ammoniums. Strong correlations between concentrations of different homologues of the same families of surfactants were observed

Preservation of parabens in water samples

Parabens are preservatives widely used in cosmetics, pharmaceutical and food products due to their antibacterial and antifungal activity. Their ubiquity in surface water and their potential adverse effects on human health and environment led to their inclusion into the French monitoring programme of aquatic environment. In order to help the laboratories improving their analytical skills regarding these chemicals, BIPEA organises since November 2016 proficiency testing schemes (PTS) according to ISO 17043 [1] for the quantification of butyl-, ethyl-, methyl- and propylparaben in freshwater. Parabens degradability in water by hydrolysis and photolysis raises the issue of their stability throughout the PT, especially for the samples with long delivery time or laboratories unable to perform their analyses at reception. In order to meet PT samples homogeneity and stability requirements, BIPEA conducted a comparative study on sample preservation by ascorbic acid and nitric acid. It included (i) an experimental PT for which parabens-spiked samples were proposed to the laboratories with each preservation agent separately, and (ii) a dedicated homogeneity and stability study performed by the French National Institute for Industrial Environment and Risks (INERIS). Overall preservation with nitric acid implied less dispersed results and closer to the spiking concentrations, especially for methylparaben, and a greater stability over time