The Endocrine-Disrupting Effect of Organotin Compounds for Aquatic Organisms

The first report of masculinized female gastropod mollusks was made by Blaber (1970), describing a penis-like outgrowth behind the right tentacle in spent females of the dog-whelk,

Nucella lapillus

around Plymouth, UK. The term, “imposex”, however, was defined by Smith (1971), meaning imposed sexual organs, to describe the syndrome of a superimposition of male genital tracts, such as penis and vas deferens, on female gastropods. Imposex is thought to be an irreversible syndrome (Bryan et al. 1986). Reproductive failure may be brought about in severely affected stages of imposex, resulting in population decline and/or mass extinction (Gibbs and Bryan 1986, 1996). Imposex is known to be induced in many species by trib-utyltin (TBT), and also by triphenyltin (TPT) released from antifouling paints on ships and fishing nets (Bryan et al. 1987, 1988; Gibbs et al. 1987; Horiguchi et al. 1995, 1997a).