Potential of Nassarius nitidus for monitoring organotin pollution in the lagoon of Bizerta (northern Tunisia)

Imposex and butyltin burden were assessed in Nassarius nitidus, Bolinus brandaris and Hexaplex trunculus collected at five stations in the Bizerta lagoon. Biological analysis showed that imposex followed type (a) in N nitidus (distal evolution), against type (d) in the two muricids (proximal evolution). Imposex indices were higher in sites located nearby sources of tributyltin and N nitidus was the least affected species of the five sites, followed by B. brandaris and H. trunculus. Butyltin analysis showed lower accumulation in N nitidus followed by H. trunculus and B. brandaris. This study has allowed the gathering of data on imposex in a snail studied for the first time in Tunisia (N. nitidus). It suggests the possibility of using such snail as a complementary species for organotin monitoring programs in the Mediterranean and further confirmed that H. trunculus is the most suitable species for such investigations.