Several environmental chemicals are classified as endocrine disrupting compounds (EDCs). Many of them have an effect on endocrine functions and the hormones that they secrete. Persistent organic contaminants (POPs), plasticisers (phthalates and adipates) and some trace metal elements particularly mercury are well known as EDCs. During this research, we were based on a multi-makers approach by combining physicochemical, microbiological, molecular and biological analyses (bioassays and biomarkers) using multidrug resistance bacteria to antibiotics such as environmental bioindicator and multi-matrix species (waters, sediments, plants, fishes) for a broad diagnosis of the contamination of the coast of Mahdia. The samples were collected during one year (April 2018 to March 2019) by a composite sampling technique. We started with a physical-chemical analysis of seawater samples and sediment extracts which showcased that the areas are highly qualified except Rejiche and Mellouleche coastal stations. The chromatographic analysis (DMA- 80, ICP-MS, GC-MS and GC-MS-MS) performed during this study made it possible to highlight the contamination of the dimension of Mahdia by trace elements, phthalates, adipates, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs), triphenyl phosphate (TPHP). Our results show that Posidonia leaves and fish tissues are more involved in this contamination. A microbiological study was carried out for the characterisation of the bacterial fauna showed a significant diversity with similar bacterial communities between the study areas using the DDGE technique. Indeed, a wide dissemination of resistant bacteria to antibiotics, some of which are pathogenic, has been demonstrated as a bioindicator of pollution using biochemical and molecular techniques. An in-vivo toxicological survey was performed on adult female rats for 21 days by intraperitoneal injection of environmental doses of plasticisers. This study recorded an alteration in biochemical biomarkers (oestrogen, progesterone, ASAT, ALAT, cholesterol, and APL) and modifications in the histological biomarkers in the endocrine glands (ovary, thyroid). Add to that, the use of the estrogenicity test (test YES) carried out on the coastal waters of the Mahdia Coast did not show any oestrogenic activity. Ecotoxicological tests were also realised on the samples of marine water. This study was able to demonstrate the acute toxicity of seawater using the growth test of Selenastrum capricornutum and Lepidium sativum and the test mobility of Daphnia magna, with the exception of the Microtus test. In the light of our results, this research appears to be an important scientific reference for the evaluation of the contamination of aquatic environments by endocrine disruptors in the context of biomonitoring.
|Titolo:||La mise en place d'une approche multi-bio-Essais pour un large diagnostic de la Contamination des milieux aquatiques par les Perturbateurs endocriniens|
|Data di pubblicazione:||15-mar-2021|
|Appare nelle tipologie:||Tesi di dottorato|