Organic micropollutants (PAHs, PCBs, pesticides) in seaweeds of the lagoon of Venice

Samples of seven genera of seaweeds (Ulva, Gracilaria, Porphyra, Grateloupia, Undaria, Fucus and Cystoseira), which can be used as environmental biomonitors and in several applications like human alimentation, animal feeding and cosmetics, were collected in four sampling sites in the Lagoon of Venice in spring and autumn 1999 with the aim of determining the contamination due to organic micropollutants (polychlorinated biphenyls, PCBs; chlorinated pesticides; polycyclic aromatic hydrocarbons, PAHs). On an average, most of the considered species were contaminated especially by PAHs (up to 56 ng g^–1 dry wt. (dw)) whereas concentrations of PCBs and pesticides in macroalgal tissues were significantly correlated and did not exceed 5 ng g^–1 dw. Among the studied genera the most contaminated by PAHs were Ulva, Undaria and Cystoseira. The highest concentrations of PCBs and pesticides were found in Cystoseira, Fucus and Gracilaria. The least contaminated genus was Porphyra. Although macroalgal specimens were sampled in differently contaminated areas placed from the mainland to the Lido Lagoon mouth, no quantitatively meaningful differences of concentrations were found among the sampling stations.