Two common water pollutants can function in shellfish as the female sex hormone estrogen does. However, new studies show different behavioral effects of those contaminants on two species.
Elliptio complanata is a freshwater mussel whose populations are seriously declining in the United States. Katherine Flynn of Adelphi University in Garden City, N.Y., and her colleagues exposed lab-kept mussels to the weed killer atrazine or to estrogen for a week. Atrazine has exhibited estrogenic effects in other species (SN: 11/2/02, p. 275: More Frog Trouble: Herbicides may emasculate wild males).
At an atrazine concentration of 15 parts per billion (ppb), a value permitted in U.S. waters by the Environmental Protection Agency, the mussels were 30 percent less likely to burrow than were mussels kept in clean water. Atrazine doses far higher and lower didn't impair this defensive behavior, the researchers reported in Montreal at the Society of Envir