LEAD POLLUTION IN BIVALVE SHELLS - MAR-MENOR, SPAIN

`Mar Menor is a coastal lagoon situated in the SE oi Spain (Mediterran ean Sea) with high concentrations of Ph, especially in the south. The shells of the Cerastoderma edule and Venerupis aurea bivalves demonstr ate a significant difference in Ph concentrations amongst the shellfis h living in the south (100 and 47ppm), and those living in the north w ith relatively cleaner water (13 and 7 ppm). Nevertheless, both of the se sampling points have greater concentrations of Ph than other points in the Mediterranean, which have been taken as ''controls'' for compa rison (3 and 3 ppm). The calcareous exoskeletons of these organisms ar e good indicators of the presence of minor elements in the waters.