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Chemosphere 45 (2001) 561±569

www.elsevier.com/locate/chemosphere

Size-dependent concentrations of trace metals in four
Mediterranean gastropods

Francesco Cubadda a,*, Marcelo Enrique Conti b, Luigi Campanella c

a Istituto Superiore di Sanita, Viale Regina Elena 299, I-00161 Rome, Italy
b Dipartimento di Controllo e Gestione delle Merci e del loro Impatto sull'Ambiente, Universita di Roma `La Sapienza',

Via del Castro Laurenziano 9, I-00161 Rome, Italy
c Dipartimento di Chimica, Universita di Roma `La Sapienza', P. le A. Moro 5, I-00185 Rome, Italy

Received 17 July 2000; accepted 30 November 2000

Abstract

In order to gain more information on the possible use of four gastropod species as metal biomonitors for the
Mediterranean area, the in¯uence of body weight upon Cd, Cr, Cu, Pb and Zn concentrations was studied in specimens
collected at locations with dierent degrees of environmental pollution. The selected species were the marine snails
Monodonta turbinata Born and Monodonta mutabilis Philippi, and the limpets Patella caerulea L. and Patella lusitanica
Gmelin. Signi®cant dierences between metal concentrations in individuals from dierent stations were tested by
ANCOVA on log-transformed data with log body weight as covariate. For all species a positive correlation between
metal concentrations and body weight was observed, which means that the largest individuals contained the highest
levels of metals. The inclusion of body weight as covariate in the statistical analysis explained from 81% to 99% of the
metal variability within the organisms and enabled the achievement of improvements in the detection of dierences
among sites. The four selected species provided a rather univocal picture of bioavailable metal loads at the dierent
stations of the experimental area. Except for Cd, the metal concentrations recorded at the clean stations were found to
lie in the range of the lowest values reported in the literature and can be employed as useful background levels which
can be referred to for intraspeci®c comparison within the Mediterranean area. It is concluded that in view of its dis-
tribution, unambiguous identi®cation, resistance to pollution and accumulation patterns M. turbinata has considerable
potential as a biomonitor of trace metals over the Mediterranean. Ó 2001 Elsevier Science Ltd. All rights reserved.

Keywords: Heavy metals; Trace elements; Biomonitoring; Mediterranean Sea; Baseline studies; Indicator species

1. Introduction conducive to water pollution. In order to face this situ-
ation, since 1975 a comprehensive pollution prevention
During the past three decades, the state of the and control programme sponsored and organized by
Mediterranean Sea has become a matter of growing in- major United Nations bodies and agencies ± the Medi-
ternational concern. The semi-enclosed nature of this terranean Action Plan ± was adopted by the Mediter-
water body, the characteristics of its current system and ranean states (WHO, 1995).
the increasing population density along its coastline are
One of the threats to the Mediterranean ecosystem is
* Corresponding author. Tel.: +39-06-49902533; fax: +39- metal pollution. Raised levels of several trace metals,
06-49387101. released into the marine ecosystem by natural or an-
thropogenic sources, have been reported in dierent
E-mail address: francesco.cubadda@iss.it (F. Cubadda). areas of the Mediterranean basin (Bargagli et al., 1985;
Mikac et al., 1985; Nicolaidou and Nott, 1990; Zatta

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