Marine TBT antifouling contamination in Ireland, following legislation in 1987

This account examines TBT contamination in Irish waters following its ban in April 1987 on all nets, structures, and vessels of < 25 m. Imposex in dogwhelks, a sensitive indicator for TBT, was examined in 1987 and 1993 using the following methods: the relative size of the female to male penis, female penis length, and the vas deferens sequence. In areas of high contamination female snails became sterile and some populations became extinct. The extensive 1987 survey indicated most inlets and bays had TBT contamination. In 1993, selected areas, having either salmon culture, yachts and boats, or ships, were re-examined. There was significant recovery in areas of salmon culture and small boat activity but a general increase at sites adjacent to shipping ports. At distances greater than 9 km from the main sources of TBT, indices for imposex were low.