Monitoring of coastal pollution using shell alterations in the false limpet Siphonaria pectinata

Lipid peroxidation level (LPO), shell biometry, shape, elemental content, and microstructure were studied in three populations of Siphonaria pectinata in the complex lagoon-channel of Bizerte across a coastal pollution gradient (northern Tunisia). LPO was found in higher concentrations in harbour populations, and shells had centred apex and were flattened. Shells were also thicker, particularly in the inner layer, with many fibrous inter-beds formed. Difference in crystallization pattern was observed in numerous shells from all three populations, being more common in harbours. From the control station to the contaminated stations, shell elemental changes were observed, with a decrease in Ca, P, Sr, and S and an increase in Cl, Cd, Cu, Fe, and K. All of these findings suggested that shell alterations could be used as a good biomarker for coastal contamination.