ACCUMULATION OF EXTRACTABLE ORGANIC HALOGENS (EOX) BY THE FRESH-WATERMUSSEL, ANODONTA-CYGNEA L, EXPOSED TO CHLORINE BLEACHED PULP AND PAPER-MILL EFFLUENTS

Freshwater mussels, Anodonta cygnea L., were collected in a lowly poll uted area in north-eastern France, and exposed during 28 days at three sites up and downstream of a chlorine bleached pulp and paper mill ef fluent. Water, sediment and mussel samples were collected at regular i ntervals and analyzed for halogenated organic residues using the sum p arameters AOX (Adsorbable Organic Halogen) and EOX (Extractable Organi c Halogen). The survey of the water showed a chronic contamination by organic halogens of the water and the sediment downstream of the pulp and paper mill sewer. Mussels exposed upstream of the mill showed no s ignificant variation of their EOX tissue concentration. In contrast, p rogressive accumulation of EOX occurred with the exposure time in muss els exposed downstream of the mill. No steady state of the EOX concent ration was observed after four weeks of exposure.