Assessment of imposex in the dogwhelkNucella lapillus(L.) and tributyltin along the northeast coast of England

Abstract

Summary Concentrations of tributyltin (TBT) less than 5 ng/l were recorded in most coastal water samples taken from a series of sites in north-east England during autumn 1991. Levels in the industrialized Tyne estuary still exceeded the Environmental Quality Standard (EQS) in 1991 but had fallen from values recorded in 1989–90. Coastal dogwhelk Nucella lapillus (L.) samples taken in 1991 had low concentrations of <0.01–0.03 μg TBT/g wet tissue. Dogwhelk populations were suffering from severe imposex when they were sampled in 1986, but there was clear evidence of recovery by 1991/92. Relative Penis Size Index scores declined between 1986 and 1991/92; two populations which were not breeding in 1986 (as evidenced by lack of juvenile recruitment) reproduced successfully in the years preceding 1991; and dogwhelk abundance on the shore increased over the study period.