PM09 Sediment Quality Assessment Cases
Exhibit Hall
8:00 AM - Monday
(PM151) Disruption of Pheromone Communication of Mud Snails Exposed to Tin Tetrachloride and Arochlor.
Wise, M.1, McClellan-Green, P.1, Rittschof, D., 1 Duke University Marine Laboratory, Beaufort, NC, USA
ABSTRACT- Tin tetrachloride is a weak androgen and inducer of imposex in mud snails (Romano et al, in review). Polychlorinated biphenyls (PCBs) such as Arochlor 1254 are estrogenic. Tin compounds alone or tin compounds in combination with PCBs have been shown to impair the sexual behavior of male fish, yet PCBs alone have not found to significantly influence behavior (Nakayama et. al, 2004). During the breeding and spawning season, we assessed the behavioral responses of mud snails Ilyanassa obsoleta to sex specific pheromones. Sexually active snails of both sexes were collected while they were copulating and were tested in bioassays after 10 and 20 days of sub-lethal aqueous exposure to tin tetrachloride (20 ng/liter), Arochlor 1254 (3 
g/liter ), or both tin tetrachloride and Arochlor 1254. Controls were exposed to vehicle only. Movement activity appeared similar in all groups. Male snails exposed to both compounds stopped responding to female pheromone and began responding to male pheromone. Similarly, female snails exposed to the compounds stopped responding to male pheromone and began responding to female pheromone. At sub-lethal levels both tin tetrachloride and Arochlor impact mud snails by disrupting normal pheromone-mediated behaviors and cause snails of either sex to behave as if they were of the opposite sex. Tin compounds, PCBs, or the combination disrupt pheromone communication in mud snails. This work supports Straw and Rittschof (in press) who reported behavioral castration of imposex as well as morphologically normal mud snails from a high imposex environment.
Key words: pheromones, Gastropods, Ilyanassa, obsoleta