Nassarius reticulatus (Nassariidae: Gastropoda) as an indicator of tributyltin pollution before and after TBT restrictions

Abstract

Between 1984 and 1993, levels of imposex (the induction of male characters including a penis on females) were measured in gastropods Nassarius (Hinia) reticulatus (L.) at localities in south-west England. Since tributyltin (TBT) was thought to cause imposex, concentrations in tissues and sea-water were also determined. Measurements made prior to the restriction of TBT usage in 1987 showed that intensities of imposex were related to TBT levels in females. Tissue concentrations were also related to those of sea-water and concentration factors (dry tissue/water) were approximately 30,000 at 10 ng Sn I 1 and 75,000 at 1 ng Sn I 1 . Penis development in females was initiated at about 1 ng Sn I 1 and in this respect JV. reticulatus appears less sensitive to TBT than the dog-whelk Nucella lapillus.As result of the TBT restrictions, concentrations in sea-water and tissues at some of the more polluted sites decreased by factors of 5-10 times between 1987 and 1993. However, population imposex declined very slowly. This was attributed to the longevity of the snails, the slow decline of penis-length in older females and the limited recruitment of less-affected females.It was concluded that N. reticulatus is a useful alternative to N. lapillus as an imposexbased TBT indicator at contaminated sites. However, when environmental TBT concentrations are declining fairly rapidly, analysis of N. reticulatus tissues provides a far better indication of change than measurements of population imposex.

Biomonitoring organotin pollution with gastropods and mussels

“…This was conclusively shown for Nucella lapillus (e.g. Bryan et al 1986) and also for Nassarius reticulatus after both field (Stroben et al 1992b, Bryan et al 1993, Huet et al 1995, Barreiro et al 2001, Barroso et al 2002a) and laboratory (Stroben et al 1992a, Bettin et al 1996, Barroso et al 2002b studies. The present work adds to this database with a regional survey, where the relationship between RPLI and TBT (Fig.…”

“…2) is similar to that described in those previous reports. For instance, both Bryan et al (1993) (data for pre-restriction years 1985-87) and Barroso et al (2002a) also found a sharp RPLI increase for TBT up to around 200 ppb Sn DW. At higher concentrations, however, while data in Barroso et al (2002a) tended to a plateau at approximately 85% for TBT up to 1400 ppb Sn DW, the few pre-restriction data in Bryan et al (1993) suggest a positive slope up to 500 ppb Sn DW, which is now confirmed to be significant over an even wider TBT range.…”

“…Although all authors agree on the value of imposex in Nassarius reticulatus for biomonitoring TBT pollution, special attention must be paid to Bryan et al (1993) since this work includes observations on the effect of the 1987 UK restrictions on TBT usage. There, it is shown that RPLI data (sets for 1989-90 and 1991 to 1993) become shifted to the left as tissue TBT levels decline markedly following the 1987 partial ban, while the vertical range of RPLI is only slightly reduced; the latter occurs because the decrease of female penislengths is slowed by environmental (TBT takes longer to decline in sediments than in water) and mostly biological factors (low, if any, reversibility rate of imposex, longevity of individuals and limited recruitment into populations).…”

“…Smith 1971, Gibbs & Bryan 1996. Imposex coastal monitoring focuses on Nucella lapillus (L.), but Nassarius reticulatus (L.) has been suggested as a suitable alternative for southern OSPAR areas; other than its wider distributional range, the latter gastropod has recognised ad-vantages such as its presence in soft bottoms, its tolerance of brackish waters and its moderate sensitivity to TBT (Stroben et al 1992b, Bryan et al 1993, Huet et al 1995. Indeed, N. reticulatus has recently been used to assess OT pollution at these latitudes at both national (Barroso et al 2002a) and more local (Barreiro et al 2001) scales.…”

Hydrobia ulvae imposex levels at Ria de Aveiro (NW Portugal) between 1998 and 2007: a counter-current bioindicator?

“…On the contrary, N. lapillus accumulates TBT preferentially via water and food (mainly mussels and barnacles which, by their turn, accumulate TBT from the water column) and so the levels of imposex in the dog-whelk predominantly indicates the level of pollution in the water. 15,36,37 Similarly to H. ulvae, N. reticulatus is a sediment-dweller, adults feed on carrion and do not ingest substrate particles. This nassarid is a scavenger 38 in which food was described as contributing more than half of the TBT body burden, 36 minimizing the effect of the direct uptake by the contact with its internal/external body surface.…”