Hydrologic Assessment of Sites Where Frog Malformations are Present in Minnesota

Abstract

As part of an interdisciplinary study of frog malformations, the U.S. Geological Survey and Minnesota Pollution Control Agency are characterizing the hydrologic setting and water quality of three surface-water sites in Minnesota. Frog malformations have been unusually high at these sites, at times greater than 20 percent of the total frog population has been malformed. Water-level and hydraulic data have been collected to determine the flow direction and gradient between ground and surface water. Water-quality and bed-sediment samples were collected at the sites during egg, tadpole, and metamorph stages of frog growth. These samples were analyzed for major ions, trace metals, nutrients, and pesticides. The specific conductance of water at or adjacent to two of the three sites was very low (less than 200 ÎS/cmî), suggesting that minimal ground water is flowing into these surface water bodies, with rain water being the main hydrologic input. Water-level data collected at these sites supports this hypothesis.

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Jones, P.M., Magner, Joseph, Rosenberry, Don, and Thurman, E.M., 2000, Hydrologic assessment of sites where frog malformations are present in Minnesota [abst.]: Emerging Issues Conference, Minneapolis, Minnesota, June 7-8, 2000.

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