R4 PM Effects and Risk Assessment of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems
Thursday, 17 November 2005: 1:50 PM - 5:30 PM in Ballroom 4

(ROG-1117-829066) Effect of predator cues on native tadpoles (Hyla chrysoscelis) exposed to fluoxetine (Prozac^®).

Rogers, E¹, Maerz, J², Davis, A², Black, M¹, ¹ Interdisciplinary Toxicology Program, Department of Environmental Health Science, University of Georgia, Athens, GA, USA²

ABSTRACT- Fluoxetine (Prozac^®) has been detected at low concentrations in surface waters and has the potential to affect non-target aquatic species, including developing amphibians. In a previous study conducted in our laboratory, Xenopus laevis tadpoles exposed to environmentally relevant concentrations of fluoxetine (0.059 ppb) exhibited limb malformations and reductions in mass at metamorphosis. Metamorphosis was also delayed at a higher concentration (29.5 ppb); however, this concentration exceeds environmental levels. Because our study used an exotic species and tadpoles were exposed to fluoxetine individually in small aquaria, it is difficult to extrapolate these results to native tadpoles developing under natural conditions. The aim of the present experiment is to expose native tadpoles to fluoxetine under natural densities with the added stress of a predator. Studies have shown that the presence of a predator can reduce tadpole feeding and delay metamorphosis. Since fluoxetine has been shown to delay metamorphosis at high concentrations, we hypothesize that this effect may be seen at lower concentrations with the addition of a predator. Groups of 20 gray tree frog tadpoles (Hyla chrysoscelis) will be exposed in 50 L containers to 0 - 0.2 ppb fluoxetine (n = 8 per concentration). Half of the replicates will receive a caged dragonfly larva, while remaining replicates will receive an empty cage. Exposure will begin early in development and continue through metamorphosis and will take place in a greenhouse under natural temperature and photoperiod. Each week, a subset of tadpoles will be staged and weighed, and daily observations for forelimb emergence, tail resorbtion, survival and malformations will be conducted. Results will be compared across treatments to determine if fluoxetine alone or with predator addition will impair development. We predict that the additional stress of a predator will produce a greater response than fluoxetine alone.

Key words: fluoxetine, pharmaceutical, Hyla chrysoscelis, amphibian