Validation de l'utilisation des stéroïdes en tant qu'outil de traçage de l'origine des contaminations fécales des eaux de surface

275 p.Faecal contaminations from human and animal wastes not only contribute to the degradation of aquatic systems but also affect water quality posing threat to human health from exposure to pathogens. To reduce these risks and improve water quality, it is necessary to develop of tools capable of identifying faecal contamination sources. This issue is exacerbated in Europe by the hardening of guidelines for bathing waters and shellfish waters and the obligation to identify and prioritize sources of contamination. The aim of this thesis is to validate the use of steroids as a tool for tracing the origin of faecal contamination in surface waters. The method is based on principal component analysis of six fecal stanols. The scientific approach was conducted in three steps, from molecular scale to the watershed scale. The specificity of steroids and the homogeneity of sources were studied on bovine and porcine manures and on influent, effluent and sludge of waste water treatment plant. Then the conservation and the persistence of the steroid fingerprint were evaluated during the transport of raw samples to the environment receiving by experiments under controlled conditions. Finally, the method developed has been validated at the scale of two watersheds impacted by recurrent multi-sources contaminations. All the results obtained in this work lead to validate the use of steroids as an operational tool to trace faecal sources contamination.Les contaminations fécales d'origine humaine ou animale contribuent à la dégradation des écosystèmes et affectent la qualité de l'eau avec des risques pour la santé publique par l'exposition à des agents pathogènes. Afin de réduire ces risques et d'améliorer la qualité de l'eau, il est nécessaire de développer des outils capables d'identifier les sources de contaminations fécales. Cet enjeu est exacerbé en Europe par le durcissement des directives sur les eaux de baignade et les eaux conchylicoles et l'obligation de procéder à l'identification et à la hiérarchisation des sources de contaminations. Cette thèse s'est attachée à valider l'utilisation des stéroïdes en tant que traceurs des sources de contaminations fécales des eaux de surface. La méthode utilisée est basée sur une analyse en composante principale de six stanols fécaux. L'approche scientifique a été menée en trois étapes, de l'échelle moléculaire à l'échelle du bassin versant. La spécificité des stéroïdes et l'homogénéité des sources ont été étudiées sur des déjections bovines, porcines et sur des influents, effluents et boues de stations d'épuration domestiques. Puis, la conservation et la persistance des empreintes stéroïdes ont été évaluées au cours du transport des échantillons sources vers le milieu naturel récepteur par des expérimentations en conditions contrôlées. Enfin, la méthode développée a été validée à l'échelle de deux bassins versants sujets à des contaminations fécales récurrentes multi-sources. L'ensemble des résultats obtenus au cours de ce travail permettent de valider l'utilisation des stéroïdes en tant que traceurs opérationnels de l'origine des contaminations fécales

Comparing the Spectroscopic and Molecular Characteristics of Different Dissolved Organic Matter Fractions Isolated by Hydrophobic and Anionic Exchange Resins Using Fluorescence Spectroscopy and FT-ICR-MS

Despite the environmental significance of dissolved organic matter (DOM), characterizing DOM is still challenging due to its structural complexity and heterogeneity. In this study, three different chemical fractions, including hydrophobic acid (HPOA), transphilic acid (TPIA), and hydrophilic neutral and base (HPIN/B) fractions, were separated from bulk aquatic DOM samples, and their spectral features and the chemical composition at the molecular level were compared using both fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The HPIN/B fraction was distinguished from the two acidic fractions (i.e., HPOA and TPIA) by the EEM-PARAFAC, while the TPIA fraction was discriminated by using the molecular parameters derived from the FT-ICR MS analyses. Statistical comparison suggests that the spectral dissimilarity among the three chemical fractions might result from the acido-basic properties of DOM samples, while the differences in molecular composition were more likely to be affected by the hydrophobicity of the DOM fractions. The non-metric multidimensional scaling map further revealed that the HPOA was the most heterogeneous among the three fractions. The number of overlapping formulas among the three chemical fractions constituted only <5% of all identified formulas, and those between two different fractions ranged from 2.0% to 24.1%, implying relatively homogeneous properties of the individual chemical fractions with respect to molecular composition. Although employing chemical fractionation achieved a lowering of the DOM heterogeneity, prevalent signatures of either acido-basic property or the hydrophobic nature of DOM on the characteristics of three chemical isolated fractions were not found for this study

Validation de l'utilisation des stéroïdes en tant qu'outil de traçage de l'origine des contaminations fécales des eaux de surface

Les contaminations fécales d origine humaine ou animale contribuent à la dégradation des écosystèmes et affectent la qualité de l eau avec des risques pour la santé publique par l exposition à des agents pathogènes. Afin de réduire ces risques et d améliorer la qualité de l eau, il est nécessaire de développer des outils capables d identifier les sources de contaminations fécales. Cet enjeu est exacerbé en Europe par le durcissement des directives sur les eaux de baignade et les eaux conchylicoles et l obligation de procéder à l identification et à la hiérarchisation des sources de contaminations. Cette thèse s est attachée à valider l utilisation des stéroïdes en tant que traceurs des sources de contaminations fécales des eaux de surface. La méthode utilisée est basée sur une analyse en composante principale de six stanols fécaux. L approche scientifique a été menée en trois étapes, de l échelle moléculaire à l échelle du bassin versant. La spécificité des stéroïdes et l homogénéité des sources ont été étudiées sur des déjections bovines, porcines et sur des influents, effluents et boues de stations d épuration domestiques. Puis, la conservation et la persistance des empreintes stéroïdes ont été évaluées au cours du transport des échantillons sources vers le milieu naturel récepteur par des expérimentations en conditions contrôlées. Enfin, la méthode développée a été validée à l échelle de deux bassins versants sujets à des contaminations fécales récurrentes multi-sources. L ensemble des résultats obtenus au cours de ce travail permettent de valider l utilisation des stéroïdes en tant que traceurs opérationnels de l origine des contaminations fécales.Faecal contaminations from human and animal wastes not only contribute to the degradation of aquatic systems but also affect water quality posing threat to human health from exposure to pathogens. To reduce these risks and improve water quality, it is necessary to develop of tools capable of identifying faecal contamination sources. This issue is exacerbated in Europe by the hardening of guidelines for bathing waters and shellfish waters and the obligation to identify and prioritize sources of contamination. This thesis is to validate the use of steroids as a tool for tracing the origin of faecal contamination in surface waters. The method is based on principal component analysis of six faecal stanols. The scientific approach was conducted in three steps, from molecular scale to the watershed scale. The specificity of steroids and the homogeneity of sources were studied bovine and porcine manures and in influent, effluent and sludge of waste water treatment plant. Then the conservation and the persistence of the steroid fingerprint were evaluated during the transport of raw samples to the environment receiving by experiments under controlled conditions. Finally, the method developed has been validated at the scale of two watersheds impacted by recurrent multi-sources contaminations. All the results obtained in this work lead to validate the use of steroids as an operational tool to trace faecal sources contamination.RENNES1-BU Sciences Philo (352382102) / SudocRENNES-Géosciences (352382209) / SudocSudocFranceF

Comparing the Spectroscopic and Molecular Characteristics of Different Dissolved Organic Matter Fractions Isolated by Hydrophobic and Anionic Exchange Resins Using Fluorescence Spectroscopy and FT-ICR-MS

Despite the environmental significance of dissolved organic matter (DOM), characterizing DOM is still challenging due to its structural complexity and heterogeneity. In this study, three different chemical fractions, including hydrophobic acid (HPOA), transphilic acid (TPIA), and hydrophilic neutral and base (HPIN/B) fractions, were separated from bulk aquatic DOM samples, and their spectral features and the chemical composition at the molecular level were compared using both fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The HPIN/B fraction was distinguished from the two acidic fractions (i.e., HPOA and TPIA) by the EEM-PARAFAC, while the TPIA fraction was discriminated by using the molecular parameters derived from the FT-ICR MS analyses. Statistical comparison suggests that the spectral dissimilarity among the three chemical fractions might result from the acido-basic properties of DOM samples, while the differences in molecular composition were more likely to be affected by the hydrophobicity of the DOM fractions. The non-metric multidimensional scaling map further revealed that the HPOA was the most heterogeneous among the three fractions. The number of overlapping formulas among the three chemical fractions constituted only <5% of all identified formulas, and those between two different fractions ranged from 2.0% to 24.1%, implying relatively homogeneous properties of the individual chemical fractions with respect to molecular composition. Although employing chemical fractionation achieved a lowering of the DOM heterogeneity, prevalent signatures of either acido-basic property or the hydrophobic nature of DOM on the characteristics of three chemical isolated fractions were not found for this study

Fractionnement et concentration de la matière organique dissoute par ultrafiltration/osmose inverse

National audienc

Exploration of changes in the chemical composition of sedimentary organic matter and the underlying processes during biodegradation through advanced analytical techniques

International audienceAlthough the scientific community widely investigated the organic matter biodegradation processes, only a limited number of studies have explored the molecular changes of this material while its structure, composition, and origin play a key in these processes. Methodology. In this context, we decided to examine the effects of the biodegradation on the chemical composition of sedimentary organic matter and to explore the underlying mechanisms. We conceived a laboratory-based degradation experiment utilizing organic-rich sediments artificially composed of two contrasting organic matter end-members (i.e., soil and algae) under two oxygen conditions. The sediment samples before and after incubation were then analyzed via laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry for molecular characterization and via thermally assisted hydrolysis and methylation gas chromatography–mass spectrometry in order to offer insights into the mechanisms driving biodegradation processes. Results. Our results from molecular characterization unveiled distinct pathways of biodegradation contingent upon the source material. Moreover, they hinted at a predilection for altering high molecular weight compounds like lignin/CRAM and CAS compounds, manifesting as a conversion into lower molecular weight counterparts. Furthermore, the complementary findings from biomarker analyses underscored the influence of environmental factors - specifically oxygen conditions and microbial communities - on organic matter decomposition. Discussion. Although this study is a controlled laboratory experiment and more studies are needed, it demonstrated the intricate interplay among chemical, biological, and environmental factors, profoundly shaping the reactivity of organic matter. This study underscores the critical need for persistent inquiry, aimed at unraveling the factors and conditions governing the diverse pathways of biodegradation

Steroids: markers of faecal contamination

1 p.The faecal pollutions contribute to the degradation of aquatic ecosystems, affect water quality and thus generate public health problems. In a context of intensive agriculture, animal faeces or sludge from wastewater are applied to fields in the place of traditional mineral fertilizers. According to the implementation of the Water Framework Directive [DCE 52006/7/CE], the level of faecal contamination is based on the analysis of microbiological markers (E.coli, enterococci). However, they are not suitable for monitoring faecal pollution and are not able to distinguish the different sources of pollution. Therefore, it is necessary to develop tools to discriminate the origin of faecal contamination. Molecular markers, such as steroids can be used as indicators of faecal contamination. This study aims to propose an absolute tool that is able to differentiate a set of animal manures (cow and pig faeces) and different types from the same origin (cowpat, fresh and old cow manures, fresh and treated pig slurries and separated pig solids). The results show that cow and pig faeces have different steroids fingerprints. For cow faeces, there is an increase phytosterols amount from cowpat to cow manure. For pig faeces, there is an important heterogeneity in pig slurry sub-group. But on the diagram %C27 versus %(C28+C29), the two types of animal manures are well separated one from the other. Coupled with statistical analysis and after identification and selection of principal components, we have arrived at a model able to distinguish easily the origin of faecal contamination in agro-hydro-systems

Microbial and chemical markers: runoff transfer in pig and cow manure-amended soils

1 p.Fecal pollution affects environmental waters through spreading of animal manure and runoff of agricultural soils. However, the indicator bacteria (E. coli and enterococci) do not identify the source of the contamination and the development of fecal source tracking tools is crucial for water management and remediation. The aim of our study was to evaluate the transfer of chemical and microbial fecal markers during a runoff simulation on an agricultural plot previously spread with bovine or pig manure. Four types of markers have been analysed: 15 fecal sterols and stanols quantified by gas chromatography-mass spectrometry, chemical fingerprint obtained by 3D-fluorescence excitation-matrix spectroscopy, F-specific RNA specific bacteriophages (FRNAPH) and bacterial markers belonging to the Bacteroidales (Rum-2bac and Pig-2-Bac) and to the species Lactobacillus amylovorus. The results show that animal FRNAPH genogroups, sitostanol/coprostanol and cholestanol/cholesterol steroids ratios and tryptophan/ fulvic-like fluorescence differentiated pig and bovine fecal contamination. Sitostanol/coprostanol > 1 and cholestanol / cholesterol 1 are characteristic of pig manure amended plot. L-amylovorus and Pig2-bac were only present in runoff water collected on pig manure amended plot whereas Rum2-bac was only detected in runoff water collected on bovine manure amended plot. Combined analyses of chemical and microbial markers provide relevant information on the determination of fecal contamination during runoff on agricultural soils. The next step is to test the applicability of these markers in watercourses submitted to nonpoint source fecal pollution

Extreme Variability of Steroid Profiles in Cow Feces and Pig Slurries at the Regional Scale: Implications for the Use of Steroids to Specify Fecal Pollution Sources in Waters

International audienc