Rapport
| Résumé : | Organic micropollutants, especially Endocrine Disrupting Compounds (EDCs), are in the center of nowadays environmental concerns. They are ubiquitous in our everyday products and materials. Numerous researches have shown the wide presence of EDCs in urban wastewaters and the low efficiency of the wastewater treatment plants in their removal. Researchers have repeatedly highlighted the harmful potential effects caused by EDCs to various human and wildlife endpoints. Among the EDCs family, the estrogenic EDCs (e-EDCS) are the compounds of most concern. Within this context, developing new techniques of removal of EDCs in wastewaters is essential.This work is incorporated within the framework of an inter-university research project, the OXEROM, studying the development of a process of degradation of wastewaters organic micropollutants by enzymatic way. The long-term objective of this work is to rely on the researches done within the OXEROM project in order to develop the scaling-up and the industrial implementation of the micropollutants enzymatic degradation process. The focus is set on the e-EDCs and their associated estrogenic activity. The work presented here is a preliminary requirement to the mentioned long-term objective. It focuses on the methods of analysis of estrogenic activity of water. A theoretical and experimental comparison study of the different existing methods of analysis of the estrogenic activity in water was carried out in order to implement them in the e-EDCs enzymatic degradation process. The goal is to develop these methods as measurement tools in order to do iterative kinetic tests and study kinetic curves of estrogenic activity removal by the enzymatic degradation process.A large literature review was made to gather and theoretically compare the existing methods of estrogenic activity analysis. From the literature review, several of the most relevant methods were chosen to be tested. The Yeast Estrogen Screen assay, the Lyticase-assisted Yeast Estrogen Screen assay, and the ER-CALUX assay have been tested so far. An analytical method, HPLC coupled with UV detection, has been partially tested and will be more investigated. For all bioassays, experimental and adjusted dose-response curves were obtained for four e-EDCs (17β-estradiol as the standard, bisphenol A, nonylphenol and triclosan) in various solvents. The estrogenic potencies of the tested e-EDCs were calculated and the dose-response curves were expressed in Estradiol Equivalents (EEQs) for bisphenol A, nonylphenol and triclosan. The methods were then used to assess the enzymatic degradation process, by obtaining kinetic curves of enzymatic degradation of several e-EDCs concentrations (17β-estradiol and bisphenol A) in synthesized water.The obtained kinetic and dose-response curves were compared for each method in terms of sensitivity, precision and robustness. A general discussion about the methods was finally carried out in order to compare their feasibility, their costs, and their applicability as measurement tools in the developed enzymatic degradation process.Further investigations will be made in the coming months about the methods of analysis of estrogenic activity in water, mostly by extending the ER-CALUX study and by testing other methods, such as non-cellular assays or in vivo assays. The work will also be more focused on the development and study of the enzymatic process, through the performance of additional degradation tests in various conditions (real wastewaters, mixture of e-EDCs, varying pH and temperature, etc.) where the methods of estrogenic activity analysis will be systematically used as measurement tools. |
