Imposex in Bolinus brandaris from the Ria formosa lagoon (southern Portugal): usefulness of "single-site baselines" for environmental monitoring.

The present study aimed at creating a so called "single-site baseline" (SSB) of imposex in the purple dye murex (Bolinus brandaris) from the Ria Formosa lagoon (Algarve coast, southern Portugal), at the moment that the IMO Antifouling System Convention (banning globally the use of organotin compounds in antifouling paints on ships' hulls) entered into force (September 2008). In the context of monitoring long-term temporal trends of pollution levels, SSBs are proposed whenever it is difficult to obtain adequate numbers of bioindicator specimens in most of the study area or if significant short-term variability in imposex levels is likely to occur. In order to deal with these constraints, this study created a SSB by sampling on a monthly-basis (from October 2008 to September 2009) in a single site considered to be representative of the Ria Formosa as a whole (vicinities of the Culatra Island) and where B.

Spatial and temporal evolution of imposex in dogwhelk Nucella lapillus (L.) populations from North Wales, UK.

Nucella lapillus imposex and organotin tissue contamination were assessed, during 2006, at twenty sites in North Wales, between Anglesey and Shell Island on the Lleyn Peninsula. Vas Deferens Sequence Index (VDSI), Relative Penis Size Index (RPSI) and the percentage of affected females (%I) were used to assess imposex levels which varied between 0.5 and 3.