Uses and quality on an oyster farming territory, the Arcachon Bay : Exposure and effects of contaminants (multidisciplinary approach)

Coastal zones are interface areas affected by many continental inputs including chemical contaminants. The significance of the pollution of coastal and estuarine areas and its involvement in the degradation of these sensitive habitats is proven.

In this context the Arcachon Basin focuses considerable environmental and social issues. Indeed, for an ecological point of view, it represents a wetland internationally recognized for its originality (it is the only notable physical discontinuity of the Aquitaine coast) and the diversity of its natural environments. Home to many important activities and values at the societal level, both in the economic field and heritage functions, the Arcachon Basin is further also affected by anthropogenic pressures of various kinds: tourist with notably boating, domestic with increasing urbanization, agricultural activities with its watershed, and industrial. The inputs of contaminants generated by these activities can be both of continental origin (runoff contribution of coastal tributaries), internal to the basin (various alterations due to boating and oyster farming), atmospheric and even oceanic.

National and regional programs (OSQUAR, RIPOST) have aimed to characterize the contamination sources in the Arcachon Bay as well as the contaminant dynamics, both in the lagoon and at the level of various freshwater tributaries flowing there. In the same time, the impacts of pollutants on two emblematic species of this lagoon (the pacific oyster Crassostrea gigas and the aquatic plant Zostera noltei) have been studied by multidisciplinary approaches conducted in situ and under controlled laboratory conditions. The major results obtained during these analyses will be described.