Résumé
The northern Mediterranean coast includes a lot of small coastal rivers and shallow coastal lagoons that are submitted to an increasing urbanisation. This study aimed to assess organic contamination by activators of the estrogens receptor (ER) and of the aryl hydrocarbon receptor (AhR) of a small Mediterranean coastal river and two coastal lagoons that received urban sewage effluents for many years. Our research was conducted on sediments and, in order to evaluate the distribution of organic contaminants, we exposed mussels and semi-permeable membrane devices (SPMDs) in two coastal lagoons after the stop of the sewage discharge. We finally sampled marine sediment around a submarine outfall that are nowadays receiving the treated wastewater. Chemical analysis of polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls and nonylphenols (NPm) was performed along with in vitro bioassays using MELN and PLHC-1 cell lines, which allowed detection of estrogenic and dioxin-like compounds, respectively. Chemical analysis and in vitro bioassays established a common pattern of contamination, i.e. sediments sampled downstream from the old sewage discharge were heavily impacted (PAH concentrations ranged from 236 to 2879 ng/g dw and from 142 to 1912 ng/g for NPm) and contamination was moderate from sediments sampled upstream (PAHs concentrations ranged from 150 to 327 ng/g dw). Around the submarine outlet, the sediment was not very impacted after a year of wastewater emission (from 21 to 42 ng/g dw for PAHs). In coastal lagoons, NPm could be quantified in sediments, SPMD and mussels. The concentrations observed in mussels (up to 3518 ng/g dw) would indicate that concentration of particulate contaminants in the water column is high even after the stop of the sewage discharge.