Title

Does metamorphosis increase the susceptibility of frogs to highly hydrophobic contaminants?

Document Type

Article

Publication Date

2006

Publication Title

Environmental Science and Technology

Volume

40

Issue

5

First Page

1491

Last Page

1496

DOI

10.1021/es0515506

Abstract

The purpose of this study was to determine whether the process of metamorphosis in amphibians increases the chemical activity of hydrophobic contaminants such as polychlorinated biphenyls (PCBs). We conducted an experiment in which green frog tadpoles were orally dosed with a PCB mixture; then placed into clean water to eliminate the chemicals as metamorphosis occurred. On several sampling dates before and during metamorphosis, organisms were sacrificed and analyzed to determine lipid contents and concentrations of individual PCB congeners. The majority of the PCBs studied in this experiment showed increases in chemical activity (fugacity) as a result of the physical changes that occurred during amphibian metamorphosis. A positive relationship was observed between PCB hydrophobicity and the magnitude of the fugacity increase. We determined that the fugacity of a persistent PCB congener will increase during green frog metamorphosis if its log KOW value is greater than 5.85. The fugacity of some of the more highly hydrophobic PCBs increased during metamorphosis by up to a factor of 4. Because of the rapid increases in chemical activity that were observed during metamorphosis, we conclude that toxicity tests involving hydrophobic organic contaminants should be conducted not only on tadpoles or adult frogs, but also on metamorphosing amphibians. © 2006 American Chemical Society.

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