Since 1994 the lagoon of Boughrara located in the south western coast
of Tunisia was a seat of repeated episodes of 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, seawater and bivalves collected from Boughrara
during the algal bloom period were analysed for Cd, Cr, Hg, Pb, Cu and
Al content using the atomic absorption spectrometry.The average of the
metals and heavy metals concentrations in clams flesh and shells were
lower or in the range of the European Union regularity limits and
exhibited the following decreasing order:
Al>Cu>Cd>Cr>Pb>Hg. Levels were ranging between 11.541
mg/kg and 0.025 mg/kg wet weights. For seawater and 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
