Accumulation of organotin compounds in the common whelk Buccinum undatum and the red whelk Neptunea antiqua in association with imposex

摘要

Several species of the subclass Prosobranchia are considered to be suitable organisms for monitoring long-term effects of triorganotin (TOT) compounds. This study utilized Buccinum undatum and Neptunea antiqua from the North Sea and the Irish Sea. Morphological alterations in the genital system (imposex phenomena), the histological structure of the gut, and the gonads were studied. TOT concentrations in soft body tissue and shells were determined. Females of both species displayed imposex phenomena (pseudohermaphroditism). The percentage of altered females per station ranged from 0 to 90% in B. undatum and from 0 to 29% in N. antiqua. Imposex index values in B. undatum reached 1.09 near Helgoland and 0.86 in N. antiqua sampled at 25 nautical miles from the Scottish northeast coast. Organotin compounds were detected in the soft bodies of snails from all stations. A chi-square analysis revealed a significant correlation between imposex stages and TOT concentrations in B. undatum but not in N. antiqua. Tributyltin (TBT) in B. undatum ranged from 1.0 to 15.9 ng g-1 wet weight (Irish east coast). TBT concentrations in N. antiqua were higher and ranged from 2.2 to 25.7 ng g-1. In both species, organotin compounds in the shells were below detection limits. Despite high TBT concentrations in soft tissues and the occurrence of imposex (offshore and inshore), female gonads were in good shape and no signs of limited reproductive capacity were found. Histological findings indicate that TBT does not contribute considerably to mortality in the common whelk.