Composition organique de boues résiduaires de stations d'épuration lorraines (caractérisation moléculaire et effets de la biodégradation)

Cette étude s'est intéressée à la caractérisation moléculaire du contenu organique de boues résiduaires de stations d'épuration de la région Lorraine. Les quarante huit échantillons collectés proviennent de stations domestiques de différentes tailles (rurales, petites urbaines et urbaines), de stations industrielles (papeteries) et de stations agro-alimentaires (laiteries et fromageries). Le premier volet développé au cours de cette étude a permis de dresser l'inventaire des composés présents dans les boues d'épuration (i) sous forme libre (fraction organique soluble- FOS) et (ii) sous forme liée à la structure macromoléculaire (fraction organique insoluble- FOI). A cette fin, les outils analytiques respectivement utilisés sont la GC-MS d'une part, et la THM-GC-MS et Py-GC-AED d'autre part. Les résultats de l'analyse de la FOS et de la FOI fournissent une information équivalente dans la mesure où ils permettent de différencier les boues selon leur origine (agro-alimentaire, industrielle ou domestique). Une empreinte moléculaire spécifique à chaque type de boues a ainsi pu être définie. Par ailleurs, l'ensemble des boues domestiques est caractérisé par un fonds géochimique pétrolier, témoignant d'une pollution diffuse commune. Une variabilité autour de ce fonds géochimique a également pu être identifiée pour certaines boues domestiques, sans relation avec la taille de la station, ni le degré d'industrialisation de la région. Ces variations, essentiellement observées au niveau de la FOS, peuvent par contre être imputées à des pollutions ponctuelles ou accidentelles dans le système de collecte des eaux usées domestiques. Ce travail a pour but de fournir, à terme, des paramètres moléculaires d'aide au suivi et au contrôle des réseaux de collecte des eaux usées. Le deuxième volet de ce projet s'est intéressé à l'étude des effets de la biodégradation sur le contenu organique des boues. Afin de simuler les processus de dégradation, quatre échantllions ont été incubés à 24C pendant 140 jours. L'analyse couplée de la FOS et de la FOI des échantillons biodégradés a permis de déterminer les grandes tendances de l'évolution du contenu organique au cours des expérimentations. Un schéma réactionnel global de biodégradation peut ainsi être proposé: l'altération de la structure macromoléculaire de la FOI libère des composés extractibles, dégradés eux-mêmes en composés de plus bas poids moléculaire ou minéralisés. Par ailleurs, cette étude a permis de déterminer des indices de biodégradation ainsi que des marqueurs organiques résistants à cette biodégradation.This study deals with the molecular characterisation of the organic content of sewage sludges from Lorraine (Northeast of France). The 48 samples collected come from domestic wastewater treatment plant of different capacities (rural, small urban and urban) and from depuration stations treating dairy, cheese dairy and paper-mill effluents. The first part of this study enabled to make the inventory of the compound present in sewage sludges (1) under free form (soluble organic fraction - SOF), and (ii) Iinked to the macromolecular structure (insoluble organic fraction - lOF). To achieve that, the analytical tools used were respectively GC-MS on the one hand, and THM-GC-MS and Py-GC-AED on the other hand. The results of the analysis of the SOF and lOF provide equivalent information ln that they enable the differentiation of siudges according to thelr origin (food-processing, paper-mlli or domestic). A molecular fingerprint specific to each type of sludge was thus defined. Besides, all the domestic sludges are characterised by a geochemical petroleum background which testifies to a common diffuse pollution. Moreover, a variability in this geochemical background was observed for some domestic sludges, regardless of the size of the station, or of the degree of industrialisation of the region. These variations, which are essentially observed in the SOF, can be attributed to punctual or accidental pollution in the sewer system of domestic wastewater. The eventual goal of this work ls to provide molecular parameters in order to improve the monitoring and the control of wastewater sewer systems. The second part of this project studies the effects of biodegradation on the organic content of sewage sludges. Four samples were incubated at 24C during 140 days in order to simulate the processes of degradation. The simultaneous analysis of the SOF and lOF of the biodegraded samples enabled the determination of the great tendencies of the evolution of the organic content during the experiments. A global pattern of biodegradation reactions can thus be proposed: the chemical degradation of the macromolecular structure of the lOF produces extractable compounds which will be either degraded themselves into lower molecular weight compounds or mineralised. Besides, organic markers resistant to biodegradation couId be determined and indexes of biodegradation proposed.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Veterinary pharmaceutical contamination in mixed land use watersheds: from agricultural headwater to water monitoring watershed

International audienceVeterinary pharmaceuticals, widely used in intensive livestock production, may contaminate surface waters. Identifying their sources and pathways in watersheds is difficult because i) most veterinary pharmaceuticals are used in human medicine as well and ii) septic or sewer wastewater treatment plants (WWTP) can release pharmaceuticals into surface water, even in agricultural headwater watersheds. This study aimed to analyze the spatiotemporal variability of animal-specific, mixed-use, and human-specific pharmaceuticals, from agricultural headwaters with intensive livestock production and a WWTP to a watershed used for Water Framework Directive monitoring. Grab sampling was performed during one hydrological year upstream and downstream from a WWTP and at three dates in seven nested watersheds with areas of 1.9-84.1km. Twenty pharmaceuticals were analyzed. Animal-specific pharmaceuticals were detected at all sampling dates upstream and downstream from the WWTP and at concentrations higher than those of human-specific pharmaceuticals. The predominance of animal-specific and mixed-use pharmaceuticals vs. human-specific pharmaceuticals observed at these sampling points was confirmed at the other sampling points. Animal-specific pharmaceuticals were detected mainly during runoff events and periods of manure spreading. A large percentage of mixed-use pharmaceuticals could come from animal sources, but it was difficult to determine. Mixed-use and human-specific pharmaceuticals predominated in the largest watersheds when runoff decreased. In areas of intensive livestock production, mitigation actions should focus on agricultural headwater watersheds to decrease the number of pathways and the transfer volume of veterinary pharmaceuticals, which can be the main contaminants

Characterization of humic substances in highly polluted river sediments by pyrolysis methylation–gas chromatography–mass spectrometry

International audienceHumic substances were extracted from two sediment cores sampled in a river on the outskirts of a large city (Deûle near Lille, France) and in its highly polluted oxbow-lake. Humic acids (HA) were characterized by infrared spectroscopy and in situ pyrolysis/methylation–gas chromatography–mass spectrometry. The main results are the substantial aliphaticity of HA in the oxbow-lake at all depths, mainly due to the presence of a lipid fraction associated with the HA structure. The abundance of sterols in this fraction implies that lipids could originate from the accumulation of sewage in the oxbow-lake. Humic acids of the Deûle sediments show a different trend ; their evolution is characterized by a decrease of the pollutant inputs with increasing depth. The results demonstrate the efficiency of Py–GC–MS in identifying the different organic contributions to HA and in distinguishing natural from anthropogenic sources

Application of thermodesorption and pyrolysis-GC–AED to the analysis of river sediments and sewage sludges for environmental purpose

International audienc

Wide genome transcription and metabolome profiles reprogrammed by sucrose under xenobiotic constraints

Plants have developed strategies to adapt quickly to environmental changes. However, the regulation of these adaptive responses and coordination of signals network remains poorly understood for many environmental constraints. Indeed, signalling molecules play a central role in environmental stimuli and may coordinate plants development under environmental cues. Sucrose is the major transport carbohydrate in higher plants, in addition to its metabolic role; recent investigations suggested that sucrose impact the plasticity of plant development by controlling gene expression. Sucrose was also suggested as a ROS scavenger and as a signalling molecule. In this paper we showed that sucrose mitigated phenanthrene induced stress. Since, exogenous sucrose allowed growth and chlorophyll accumulation in the presence of high phenanthrene concentrations, whereas Arabidopsis development was blocked and seedlings were unable to accumulate chlorophyll in the presence of phenanthrene solely. To decipher the earlier molecular changes involved in sucrose tolerance to phenanthrene, wide transcriptional genes analysis and targeted metabolic profiling were carried out. We showed that sucrose driving plant response was associated with a deep reconfiguration of both genes expression and metabolites accumulation during the first hours of treatment, suggesting that sucrose, allowed plants to sustain the primary metabolism and to overcome the phenanthrene induced injuries

Development of tools to differentiate bovine, porcine and human fecal contamination in surface waters

International audienc

Development of tools to differentiate bovine, porcine and human fecal contamination in surface waters

International audienc

Des micro-organismes et des composés chimiques pour identifier les sources de contamination fécale : étude de leur persistance en microcosmes et de leur présence dans les eaux à l'échelle d'un bassin versant

La dégradation de la qualité des eaux par la pollution microbiologique représente un problème majeur de santé publique, notamment dans les eaux ou s'exercent des activité humaines. Afin de définir les actions prioritaires à mener, une meilleure connaissance de l'origine des pollution fécales est nécessaire. Cet article nous présente le développement d'une méthode innovante utilisant des marqueurs chimiques et microbiologiques permettant de différencier trois sources majeures de contamination des eaux de baignade en Bretagne: les déjections humaines, bovines et porcines