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

Abstract

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 histolog~cal structure of the gut, and the gonads were studied. TOT concentrations in soft body tissue and shells were determined. Females of both species displayed imposes phenomena (pseudohermaphroditism) The percentage of altered females per station ranged from 0 to 90% in B. undatum and from 0 to 2 9 % in N. antiqua. Imposes 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 chl-square analysis revealed a significant correlation between imposex stages and TOT concentrations in B. undaturn but not in N. antiqua. Tributyltin (TBT) in B. undatum ranged from 1.0 to 15.9 ng g-I wet weight (Irish east coast). TBT concentrations in N. antiqua were higher and ranged from 2.2 to 25.7 n g g-l 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. Histolog~cal findings indicate that TBT does not contribute considerably to mortality in the common whelk.

Imposex in two sublittoral neogastropods from the Kattegat and Skagerrak: the common whelk Buccinum undatum and the red whelk Neptunea antiqua

“…At lower imposex levels this relationship was not found. This is similar to the observations in a study from the open North Sea (Ide et al 1997). Absence of imposex in B. undatum has only been observed in few areas of the North Sea (ten Hallers-Tjabbes et al 1994, Ide et al 1997, Nicholson & Evans 1997.…”

“…Since all females of N. antiqua from the Kattegat and the majority of females from the Skagerrak were affected, this species is probably a more sensitive indicator of TBT pollution. In our study, imposex occurred more frequently than in the populations of N. antiqua from the North Sea, where 0 to 29% of the individuals had developed imposex (ten Hallers-Tjabbes et al 1996, Ide et al 1997). This suggests increased levels of TBT in Danish waters.…”

“…The lowest ∑BT concentrations were in whelks from the Skagerrak (Stn 1) with an average of 1.9 ng Sn g -1 wet wt, and the highest ∑BT concentrations were south of Sprogø (Stn 13) with an average of 24.9 ng Sn g -1 wet wt. B. undatum is thought to biotransform TBT to DBT and MBT (Ide et al 1997), and in all samples TBT forms a minor part of the ∑BT content. The ratio of TBT to ∑BT in the whelks varied from 0.05 to 0.34.…”

“…In the offshore waters of the southern North Sea, there seems to be a relationship between the intensity of commercial shipping traffic and the occurrence of imposex in the common whelk Buccinum undatum (ten Hallers-Tjabbes et al 1994). A study by Ide et al (1997) demonstrated the presence of imposex and organotin accumulation in B. undatum and the red whelk Neptunea antiqua at offshore stations of the North Sea and Irish Sea, indicating the widespread occurrence of TBT.…”

Tributyltin and imposex:no uncertainty shown

“…For instance, this journal has recently published 3 works dealing with TBT accumulation and the masculinization of female neogastropods ('imposex'), both in the field (Ide et al 1997, Ruiz et al 1998) and under experimental conditions (Davies et al 1997). We comment here on 2 important questions raised by this last paper.…”