Abstract
The Mediterranean coastal area, particularly harbors and marinas represent areas of high pollution associated with population density and activity. They are also places of refuge for many aquatic species. Preliminary studies have shown that sediments from Port Camargue subject to mandatory dredging, present an important level of copper and organotins (OTs) contamination which can affect aquatic ecosystems. In this context, the objectives of this thesis are to characterize the state of contamination in sediments and the water column, the impact of this contamination on target organisms, and identify the processes that control the dynamics of pollutants in the sedimentary column and sediment/water interface. To achieve the objectives, the study coupled in situ approach (core samples, sampling of interstitial water at the interface, caging deployment…) and a laboratory in vitro approach (sorption tests in microcosms). For this study the contamination of the sediment (particulate and dissolved phases) was performed in a first part. Secondly, the speciation of Cu, Zn and Mn as well as OSn in the harbor water was studied over a period of one year before dredging and for the six months during the dredging operations. The effects of contamination were also examined on bivalves (Ruditapes and Loripes) immersed in the water column. Finally, the copper isotopes as tracers of source of contamination were tested in this simple environment, since anthropogenic Cu comes mainly from antifouling paints. The entire study has provided insight into the future, the dynamic and bioavailability of pollutants present and past in a Mediterranean port environment heavily contaminated with Cu and OSn.