A population of the neogastropod Ocenebra erinacea sited close to the shipyard at Falmouth (Cornwall: south-west England) has been monitored over a period of 20 years for the effects of exposure to the antifouling agent tributyltin (TBT). During the years 1986 to 1995 the proportion of females sterilized through abnormal development of the oviduct increased from 36% to 87%. Despite legislative restrictions on TBT paints, in 2006 there was little improvement in the reproductive capacity of the population in that over 75% of females still showed the same abnormality. At the sampling site, levels of TBT in surface water had a background of around 2 ng Sn l−1 throughout the period of study with higher peaks up to 50 ng Sn l−1. Much of the TBT pollution in the Fal estuary and environs in recent years appears to be the result of discharges from the shipyard at Falmouth within the estuary.
