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Ozark Hellbender (Cryptobranchus alleganiensis bishopi) populations are in decrease throughout their native range with rare recruitment of young. Increased estrogenic chemical levels and alterations of physicochemical properties in their habitat may play a significant role in this phenomenon. We report here the first systematic, comprehensive study of organic chemical concentrations and physical and nutrient parameters in two rivers containing Ozark hellbender populations. Water samples were collected monthly from August 2003 to November 2004. Concentrations of 21 organic chemicals were determined using gas chromatography-mass spectrometry. Nine organic chemicals were detected. Benzyl butyl phthalate, dibutyl phthalate, bisphenol A, and beta-sitosterol were all detected >85% of the time, with median concentrations of 18 to 234 ng/L and maximum concentrations of 198 to 4141 ng/L. Individually, concentrations of nutrients and organic chemicals were much lower than those shown previously in laboratory and field experiments to have reproductive effects on amphibians. Nevertheless, hellbenders are exposed to a variety of chemicals with potential estrogenic effects. Our study establishes the basis to examine the specific effects of the detected concentrations, alone and in combination, on the Ozark hellbenders.

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