Accumulation de composés organo-halogénés extractibles (EOX) dans différents organes du bivalve d'eau douce,Anodonta cygneaL., exposéin situaux effluents d'une usine de pâte à papier blanchissant au chlore

Abstract

Accumulation of extractable organic halogens (EOX) in different organs of the freshwater mussel, Anodonta cygnea L., exposed in situ to chlorine bleached pulp and paper mill effluents Keywords : Anodonta cygnea, bioaccumulation, gills, digestive gland, gonad, AOX, EOX.Freshwater mussels, Anodonta cygnea L., were collected at a reference site and transferred to three monitoring stations located upstream (one station) and downstream (two stations) of a chlorine bleaching pulp and paper mill. During the 91 days of the experiment, water and mussels were sampled regularly at the three stations and halogenated organic micropollutants were determined using the sum-parameters AOX and EOX. The.general water quality decreased downstream of the effluent release and shows a chronic AOX contamination ; the mean AOX concentrations increased by 9 to 16 compared to the upstream station. The mussels exposed at the upstream station showed no significant variation in EOX concentrations. In contrast, a progressive EOX • accumulation was observed in the gills, digestive glands and gonads of the mussels exposed at the two downstream sites. The accumulation factors, calculated as the ratio between the final and the initial EOX concentrations varied between.3.5 and 7.4 according to the considered organ and station.