A large scale survey of the trace element (TE) contamination of Mediterranean coastal
waters was performed from the analysis of Ag, As, Cd, Cu, Hg, Ni and Pb in the bioindicator
Posidonia oceanica, sampled at 110 sites differing by their levels of exposure to
contaminants. The holistic approach developed in this study, based on the combined
utilization of several complementary monitoring tools, i.e. water quality scale, pollution
index and spatial analysis, accurately assessed the TE contamination rate of Mediterranean
coastal waters. In particular, the mapping of the TE contamination according to a
new proposed 5-level water quality scale precisely outlined the contamination severity
along Mediterranean coasts and facilitated interregional comparisons. Finally, the
reliability of the use of P. oceanica as bioindicator species was again demonstrated
through several global, regional and local detailed case studies. NB: The designations
employed and the presentation of the information in this document do not imply the
expression of any opinion whatsoever on the part of the authors concerning the legal
status of any country, territory, city or area or of its authorities, or concerning
the delimitation of its frontiers or boundaries.