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Metals Accumulation in Marine Bivalves and Seawater from the Lagoon of Boughrara in Tunisia (North Africa)

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Since 1994the lagoon ofBoughrara located in the south western coast ofTunisia was a seat of repeated episodesof harmful algal proliferation. Due to intoxications by shellfish harvested in this region the area was banned. In order to estimate the metal contribution to this phenomenon, seawaterand bivalvescollectedfromBoughrara during the algal bloomperiod wereanalysed forCd, Cr, Hg, Pb, Cu andAI content using the atomic absorption spectrometry.The average of the metals and heavymetals concentrations in clams flesh and shells wereloweror in the range of the European Union regularity limits and exhibited the followingdecreasing order:AI>Cu>Cd>Cr>Pb>Hg. Levels wereranging between 11.54I mg/kg and 0.025 mg/kg wet weights.For seawaterand inter-shell water the order was approximately the same. The lagoon of Boughrara might be considered relatively unpolluted with metals and repeated toxic algal proliferations remained unexplained.

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