Toxicity of selenium to developingXenopus laevisembryos

Abstract

Se in the form of sodium selenite is toxic to Xenopus laevis embryos and tadpoles continuously exposed to concentrations above 1 ppm. Concentrations of 2 ppm and above result in severe developmental abnormalities and increased mortality. Uptake and loss of radioactive Se from water are rapid, but depuration is not complete, indicating that some Se can remain bound by the organism. The facts that Se is toxic at low levels to Xenopus embryos and tadpoles, can cause developmental abnormalities, and accumulates in tissues suggest that increased release of Se compounds into the environment poses a potential threat to aquatic organisms. This research was sponsored by the Division of Biological and Environmental Research, U.S. Department of Energy, under contract W‐7405‐eng‐26 with the Union Carbide Corporation. C. L. Browne is a postdoctoral investigator supported by subcontract 3322 from the Biology Division of Oak Ridge National Laboratory to the University of Tennessee.