Sex Change in the Female Dog-Whelk,Nucella Lapillus, Induced by Tributyltin from Antifouling Paints

Abstract

Nucella lapillus were reared in the laboratory over a period of more than two years from hatching to maturity in waters containing tributyltin that had leached from an antifouling paint at concentrations of 1-2, 3-5, 20 and 100 ng Sn/1 in the TBT fraction. Penis and vas deferens formation in the female ('imposex') occurred at all TBT levels, development of these organs advancing further with increasing TBT concentration, the major part being observed during the first year of life. Normal egg capsule production occurred only in females held at a TBT concentration of 1-2 ng Sn/1; at higher TBT levels females were sterilised by imposex. Oogenesis was suppressed at TBT levels above 3-5 ng Sn/1 to be supplanted by spermatogenesis leading to sperm production. This effect of TBT exposure on gonadal activity in the laboratory was supported by field observations. The consequences of these findings are discussed in relation to the recovery of N. lapillus populations following legislation banning the sale of TBT paints for use on small pleasure craft.

Cytology of the outer penis epithelium ofBuccinum undatum (L.) from the arctic region — an observation of the imposex phenomenon

“…It has been investigated on a large scale in the last few years with regard to increasing TBT (tributyltin) pollution resulting from the use of antifouling paints (Bright & Ellis, 1990;Gibbs et al, 1988;Oehlmann et al, 1992;Short et al, 1989;. TBT is also used as a biocide in various formulations.…”

Ecological risk assessments of endocrine disrupting organotin compounds using marine neogastropods in Hong Kong

“…Juvenile Buccinum undatum exposed to TBT, just after hatching, showed a dosedependent proportion of the young developing male sexual characters (Mensink et al, 1996), but no follow up study has been reported to ascertain whether the functional sex ratio is altered. Gibbs et al (1988) recorded suppression of oogenesis and production of sperm in female N. lapillus raised from hatched juveniles under the influence of TBT. The reproductive function of masculinization was not determined, and was believed to be hypothetical due to the absence of sterile female in the study population.…”

“…This relationship meant that monitoring of TBT pollution can be effectively carried out based on the degree of imposex development in neogastropods in the receiving environment. Indeed, imposex in the female can occur at TBT concentration as low as 1 ng l À1 (Gibbs et al, 1988). The degree of imposex can be gauged by two main indices, namely relative penis size index (RPSI) and vas deferens stage index (VDSI) (Gibbs et al, 1988).…”

“…The degree of imposex can be gauged by two main indices, namely relative penis size index (RPSI) and vas deferens stage index (VDSI) (Gibbs et al, 1988). In general, there is a strong positive correlation between the imposex indices and ambient TBT level or distance from harbour/dockyard Gibbs et al, 1988;Horiguchi et al, 1994Horiguchi et al, , 1997Chiavarini et al, 2003).…”

Ultrastructure of oogenesis in imposex females of Babylonia areolata (Caenogastropoda: Buccinidae)

“…Histologically, apart from having the negative effects on oogenesis (Gibbs et al 1988;Oehlmann et al 1996;Horiguchi et al 2002), TBT also induces spermatogenesis in the ovaries of imposex females (Horiguchi et al 2002(Horiguchi et al , 2006. However, despite a report of extensive oocyte degeneration in Hexaplex trunculus (Axiak et al 2003), information on the effect of TBT on oogenesis in imposex females at the ultrastructural level is limited.…”