CLOTFELTER, E.C.*; INGHAM, R.R.; GESUALDI, D.A.; Providence College; Providence College; Providence College: Genistein exposure and growth of fathead minnows

We examined the effects of the isoflavone genistein on the growth and development of the fathead minnow, Pimephales promelas. Using a static-renewal test design, minnows were exposed for 96 hours to genistein dissolved in water at concentrations ranging from 10 to 1280 micrograms/L (increased by factor of 2). We monitored survival and measured body mass for eight weeks after the initial exposure period. Genistein exposure had no significant effect on minnow survival during or after exposure. There was a moderate dose-dependent effect of genistein on the rate of mass increase. Finally, there was little evidence that genistein exposure induced asymmetric growth of three bilateral structures (measured by the absolute value of R – L): the post-orbital distance, the pectoral fin length and the pelvic fin length. We discuss our results in the context of the growing literature on the effects of isoflavones on human and wildlife health.