Survey of organotin compounds in the western mediterranean UsingMolluscs and fish as sentinel organisms.

Tributyltin (TBT) and its degradation products, mono-(MBT) and dibutyltin (DBT) as well as triphenyltin (TPT) were determined inmolluscs and fish collected along the Catalan coast (Western Mediterranean). Marine molluscs (mussels, clams and snails) were sampled from three harborswith different characteristics (small vs. large boats). Two fishspecies were studied (a) the grey mullet Liza aurata sampled inBarcelona harbor and (b) the red mullet Mullus barbatus sampled alongthe coast; different tissues (muscle, liver, gills and digestive tube) wereanalysed separately. The composition of butyltin compounds was differentaccording to the organism and sampling point, but in general elevatedconcentrations of TBT were noticed in molluscs. The highest organotin residuelevels (5.4 microg/g d.w. as Sn) were detected in mussels from Masnou, arecreational marina, followed by those collected in Barcelona harbor (1.2microg/g d.w. as Sn). In contrast, no organotin compounds were detected in fishmuscle and very low levels in the other organs, being TPT the major organotinin red mullet liver.