Parental exposure of the freshwater snail Planorbella pilsbryi to copper results in transgenerational effects in offspring

Although not assessed in standard ecotoxicological tests, exposure to a toxicant that does not result in an observable adverse effect in the parents may lead to transgenerational effects. These are adverse effects observed in unexposed offspring as a result of their parents' exposure to a toxicant. The goal of this study was to investigate whether transgenerational effects are observed in freshwater snails exposed to a toxicant. Using copper (Cu) as a reference toxicant, this study investigated whether the magnitude of exposure to the parents of the freshwater snail Planorbella pilsbryi resulted in a change in sensitivity of juvenile snails to a subsequent aqueous exposure of Cu. This study also investigated whether transgenerational effects observed in juvenile snails born to exposed parents would change if the parents laid eggs after being given time to recover from their exposure to Cu. Juvenile snails born to parents that were exposed to Cu without being given time to recover had no change in their sensitivity to Cu exposure or in some cases they became less sensitive. This study also observed that when parents were given time to recover from the Cu exposure, juvenile snails tended to be more sensitive to a subsequent Cu exposure, that is, decrease in median lethal concentrations for juveniles with an increase adult exposure. This study demonstrates that exposure of parent snails to a toxicant does not necessarily result in a consistent and significant change in sensitivity of the offspring to the same toxicant.