Proceedings of the Second Mediterranean Symposium on Marine

BIOMONITORING OF ENVIRONMENTAL METLLIC CONTAMINATION
Céline LAFABRIE 1
, Buno ANDRAL2 , Lila FERRAT1 , Vanina LEONI 1
., Christine PERGENT-
MARTINI1 , Didier SAUZADE2 1 Equipe EqEL, Université de Corse, 20250 CORTE, France
2 Ifremer PAC, BP 330, 83507 La Seyne st Mer Cedex - France
ABSTRACT
As part <strong>of</strong> <strong>the</strong> MONIQUA program initiated by <strong>the</strong> Corsican Territorial Collectivity, <strong>the</strong>
biomonitoring <strong>of</strong> metallic contamination along <strong>the</strong> Corsican coast (<strong>Mediterranean</strong>) have
been carried out using Posidonia oceanica (L.) Delile as bioindicator species. The
analysis <strong>of</strong> mercury levels was realized in <strong>the</strong> belowground tissues (scales and rhizomes,
by a lepidochronological study) on three sites: Bastia, Lumio and Macinaggio. The results
show that mercury concentrations are very weak, in both tissues, for all studied sites,
compared to <strong>the</strong> literature data all over <strong>the</strong> <strong>Mediterranean</strong>, never<strong>the</strong>less, <strong>the</strong> site <strong>of</strong> Bastia
appears more contaminated than <strong>the</strong> o<strong>the</strong>rs. This result can be explained by <strong>the</strong> level <strong>of</strong>
anthropization <strong>of</strong> this site (e.g. demography). The use <strong>of</strong> a “correction factor”, based on
<strong>the</strong> relative <strong>the</strong>orical contribution <strong>of</strong> scales and rhizomes weight to <strong>the</strong> belowground
biomass allowed to highlight, for all sites, a significant decrease <strong>of</strong> mercury levels
between 1997 and 2001.
KEY WORDS: biomonitoring / mercurial contamination / Posidonia oceanica /
<strong>Mediterranean</strong> Sea
INTRODUCTION
The Directive Cadre on Water 2000/60/CE, forecasts <strong>the</strong> setting <strong>of</strong> <strong>the</strong> ecological and
chemical state <strong>of</strong> waters and associated ecosystems monitoring. In this way, <strong>the</strong> Territorial
Collectivity <strong>of</strong> Corsica initiated, in collaboration with <strong>the</strong> regions <strong>of</strong> Sardinia and Tuscany,
a communal programme INTERREG (N° MCD IIIA-03/08) aiming at setting a monitoring
<strong>of</strong> <strong>the</strong> waters and <strong>the</strong> marine littoral environment quality (MONIQUA). This monitoring
necessity is not a recent approach and, if initially it was limited to <strong>the</strong> measure <strong>of</strong> <strong>the</strong>
physico-chemical parameters and <strong>of</strong> <strong>the</strong> contaminants in <strong>the</strong> water masses and/or <strong>the</strong>
sediments (e.g. Réseau National d'Observation – RNO), it is <strong>the</strong>n extended to <strong>the</strong> living
matter using bioindicators organisms (Claisse and Cossa, 1999) allowing a real
biomonitoring. This one is based on <strong>the</strong> capacity <strong>of</strong> <strong>the</strong> bioindicator organism to
concentrate in its tissues <strong>the</strong> chemical contaminants in a proportional factor to <strong>the</strong>ir
bioavailability (Andral and Stanisière, 1999).
The interest borne to Posidonia oceanica (Linnaeus) Delile, in so far as a biological
indicator is showed by many studies for about twenty years (Pergent, 1991). The use <strong>of</strong>
this species is justified by its longevity, its benthic character, its wide geographical
repartition, its capacity <strong>of</strong> concentration towards several stable pollutants (Pergent et al.,
1995) and its capacity to memorise <strong>the</strong> mercury, which associated to <strong>the</strong> possibilities <strong>of</strong>
dating by lepidochronology, <strong>of</strong>fers <strong>the</strong> possibility <strong>of</strong> a temporal follow-up <strong>of</strong> this
contaminant (Pergent-Martini, 1998).
ACTES DU DEUXIEME SYMPOSIUM MEDITERRANEEN SUR LA VEGETATION MARINE (ATHENES, 12-13 DECEMBRE 2003)
175