Page 2 - Tranchina_alli_2004

204 L. TRANCHINA et al.

high levels of heavy metals could affect similar ecosystems (Prange and Dennison, 2000).
The status of the pollution in the Mediterranean Sea is inhomogeneous and no impact
study has isolated one particular marine organism as a direct biomonitor of the contamination
processes. P. oceanica has already been proposed as a bioindicator to record environmental
alterations (Pergent et al., 1995; 1999; Pergent-Martini, 1998; Pergent-Martini and Pergent,
2000). Geological characteristics of the meadow sites should be considered carefully to dis-
tinguish between pollution and natural contributions to chemical element concentrations.
Correlations between trace metals concentrations in plant fractions and sediments also
play a role (Maserti et al., 1988; Warnau et al., 1996; Nicolaidou and Nott, 1998;
Schlacher-Hoenlinger and Schlacher, 1998; Sanchiz et al., 2000). Extrapolation of concen-
tration values from one site to another may be confounded by several factors such as the
physiological status of the organisms, environmental variability, and the geochemical
characteristics of the habitat.

As part of a more general scientific project (MIR Project, funded by the Italian Ministero
per l’Istruzione, l’Universita` e la Ricerca), aimed to integrate different methodologies for the
environmental protection, a preliminary survey of metal and radionuclide contaminations in
P. oceanica and sediments in four sites of the north-western coast of Sicily has been carried
out (see Fig. 1). Sites have been chosen to be very similar for geochemical and lithological
features but different for proximal pollution conditions. Four heavy metals (Cu, Cd, Pb and
Zn), four natural radionuclides (40K, 210Pb, 228Ac and 214Bi) and one artificial radionuclide
(137Cs) were selected for study. Data were compared with the major, minor and trace
elements measured in sediments collected in the same sites.

The correlation between the values of heavy metal concentrations in P. oceanica and sedi-
ments could provide some hints to finding remedial actions with respect to the pollution of
anthropogenic origin. Moreover, a rough assessment of the state of the marine environment
near the north-western coast of Sicily can be obtained from the survey.

FIGURE 1 Map of the geographical area of the investigated sites and the locations of sampling.