TBT effects on the female genital system of Littorina littorea: a possible indicator of tributyltin pollution

Abstract

Specimens of the prosobranch Littorina littorea (L., 1758) collected along the East Frisian North Sea coast in summer 1993 exhibited alterations of the pallial oviduct termed as intersex in response to tributyltin (TBT) pollution. The range of TBT body burden was between 150.9 and 1289.5 g as Sn kg -l (dry wt.). Five stages of intersex development (0-4) could be distinguished and are documented with scanning electron micrographs. In stages 2-4, which can be found in the direct vicinity of harbours and marinas, the morphological malformations of the oviduct inhibit successful copulation and capsule formation, resulting in sterilization.The intersex index (ISI, calculated as the average intersex stage of a population) and the average prostate length of females were used as parameters for the determination of intersex intensities in the populations. Both indices show significant and positive correlations to the TBT body burden of L. littorea and are promising parameters for TBT biomonitoring. A comparison of TBT bioconcentration factors with populations from England and France indicates that the threshold concentration for intersex development is in the range of 15 ng TBT as Sn/l.Morphometric analyses of the midgut gland revealed no significant differences between sampling stations. In the ovary a retardation and blockage of maturation (atresia) was observed in populations close to harbours. Lytic processes in ovary follicles were observed not only at TBT exposed sites but also at reference stations.

Biomonitoring: An appealing tool for assessment of metal pollution in the aquatic ecosystem

“…The intersex index (ISI), as another parameter, indicates the reproductive capability of females in the given population. If ISI b2 in Littorina L., most females will have been sterilized [102]. Laboratory simulative experiments and field investigations show a good positive relationship existing between degrees of imposex and ambient TBT exposure levels [101,103].…”

Tributyltin biomonitoring using prosobranchs as sentinel organisms

“…The periwinkle¸ittorina littorea does not develop imposex but especially in direct proximity to harbours and marinas malformations of the female genital tract were found which were termed as intersex [28]. The female specimens affected by intersex were either characterized by the development of male features on the female pallial organs (inhibition of the ontogenetic closure of the pallial oviduct) or female sex organs were supplanted by the corresponding male formations.…”

“…The female specimens affected by intersex were either characterized by the development of male features on the female pallial organs (inhibition of the ontogenetic closure of the pallial oviduct) or female sex organs were supplanted by the corresponding male formations. The intersex phenomenon of¸ittorina littorea is a gradual transformation of the female pallial tract which can be described by an evolutive scheme with four stages [28].…”

Field test of the behavioral regulation of larval transport

“…G. bosc attaches its eggs to the substrate (Dahlberg & Conyers 1973, Fahay 1983, and therefore eggs of the second most abundant constituent of the ichythoplankton were not collected. Crepidula fornicata and Littorina littorea commonly occur from brackish to saline waters but they are most abundant at higher salinities (Wells 1965, Dahlberg & Conyers 1973, Hardwick-Witman & Mathieson 1983, Bauer et al 1995. Peak spawning by both species occurs at night during spring tides and new and full moons (Chipperfield 1951, Newell & Newell 1973, Fish 1979, Alifierakis & Berry 1980, Todd & Laverack 1991.…”