GOLEMAN, W.L.*; URQUIDI, L.J.; MCMURRY, C.S.; ANDERSON, T.A.; KENDALL, R.J.; CARR, J.A.: Amphibian Metamorphosis is Inhibited by Environmentally Relevant Concentrations of Ammonium Perchlorate
Ammonium perchlorate (AP, NH4ClO4) has been used as an oxidizer component in solid rocket propellants for more than 50 yrs. AP detection in surface and ground waters near aerospace materials storage areas, as well as the fact that perchlorate inhibits thyroidal iodide uptake, suggests that environmental AP may disrupt thyroid activity in humans and wildlife. Here we describe AP effects on development and metamorphosis in Xenopus laevis. Eggs and larvae were exposed to a range of AP concentrations and control medium for 70 days. AP inhibited thyroid-hormone-dependent aspects of growth and metamorphosis in a reversible manner. Preliminary findings indicate that environmentally relevant concentrations of AP inhibit tail resorption as determined by the EDSTAC Tier I test for thyroid hormone disruption. These effects were observed at concentrations at or below those reported in surface waters at the Longhorn Army Ammunition Plant in Karnack, TX. Our results suggest that, at these concentrations, AP may pose a threat to normal development in natural amphibian populations. (The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the 311 HSW/AFIERA or the U.S. Government. Supported in part by the U.S. Department of Defense, through SERDP under a Cooperative Agreement with the USAF, Inst. for Environ, Safety, and Occup. Health, Brooks AFB, TX).