Investigations of imposex and intersex in marine snails in Vikkilen in Grimstad in the period 2005–2014.

Summary

Tributyltin (TBT) has been used as an active agent in antifouling paint on ships since the 1960s. Due to its high toxicity, new application on ship hulls was prohibited in 2003 and after 2008 no vessels are allowed to have TBT in their antifouling coating. TBT has been shown to interfere with biological processes in a range of species. Most notably it causes disruption of the sexual development in marine snails. Internationally agreed classification of these effects has to some extent been implemented, termed intersex in the common periwinkle (Littorina littorea) and imposex in the mud snail (Nassarius reticulatus), common whelk (Buccinum undatum) and dogwhelk (Nucella lapillus). The shipyard AS Nymo in Vikkilen bay at Grimstad has been in operation since 1946, with sand blasting and recoating of hulls as important activities. Until the legislative ban on TBT this shipyard was the primary source of the extremely high levels of TBT in the sediments in Vikkilen. The sand blasting and recoating activities were terminated in 2013.