Trace metals in seagrass, algae and molluscs from an uncontaminated area in the Mediterranean

The concentrations of Cd, Cr, Cu, Pb and Zn were measured in specimens of f our marine organisms - the seagrass Posidonia oceanica (L.) Delile, the bro wn algae Padina pavonica (L.) Thivy, and the two gastropod molluscs Monodon ta turbinata Born and Patella caerulea L. - selected as possible cosmopolit an biomonitors of trace metals in the Mediterranean area. The organisms wer e collected at five coastal sites in Favignana Island (Sicily, Italy), an a rea virtually uninfluenced by anthropogenic activities. In order to gain a more complete picture of both the environmental conditions of the experimen tal area and the bioaccumulation patterns of the selected organisms, solubl e and total metal concentrations were determined in coastal water samples c ollected at the same stations. The picture of bioavailable metal loads in t he different sites of the selected area provided by the four species was ra ther univocal. An overall trend of increased metal concentrations at the st ation in which the local harbour is located was clear. On the other hand, t he metal concentrations recorded at the 'clean' stations generally fall in the range of the lowest values available in the literature and may be consi dered as useful background levels to which to refer for intraspecific compa rison within the Mediterranean area. implications in biomonitoring of the o bserved accumulation patterns, especially in the different tissues of Posid onia oceanica, are discussed. (C) 2000 Elsevier Science Ltd. All rights res erved.