PARENT SESSION
PS6 - Contaminant Effects on Amphibians & Reptiles
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P080) Evaluation of a Proposed Toxicity Testing Regime for Amphibian Species, Part 1- Metals.
Price, David1, Westerman, Albert2, Wigginton, Andrew*,1, Beiting, Michael1, Linder, Greg3, Birge, Wesley1, 1 University of Kentucky, Lexington, KY, USA2 Natural Resources and Environmental Protection Cabinet, Frankfort, KY, USA3 Heron Works, USGS/BRD/CERC Field Office, Brooks, OR, USA
ABSTRACT- Field and laboratory toxicity tests were conducted with embryo-larval (EL) stages of fish and amphibian species. Many amphibian species exhibited unusually high sensitivity to chemical stressors. In a previous paper, and updated in this study, a Chemical Hazard Index (CHI) was developed using laboratory toxicity tests for ranking amphibian species according to their sensitivity to chemical stressors and for comparisons with up to six benchmark fish species. In 573 point-to-point comparisons of amphibian and fish responses to metal exposure, amphibian species were more sensitive in 386 cases (67%). Particularly high frequencies of terata occurred in toxicity tests with inorganic mercury in which a clear dose-response relationship was observed. Xenopus laevis was also used in field with a complex tannery plant effluent. Flow-through, static-renewal, and static procedures were compared for precision and reliability. Embryo-larval LC50 values, expressed as percent effluent, were 0.4, 0.9, and 1.2 for FT, SR, and ST systems respectively. These results indicate less dependability for data obtained in static tests. Two fish species were also included in this field study. EL LC50 values were essentially the same for X. laevis (1.5) and Pimephales promelas (1.6), the fathead minnow. Oncorhynchus mykiss (rainbow trout) was more sensetive with an EL LC50 of 0.9. Amphibian species proved to be very useful in quantifying chemical stresses in the field and laboratory. The embryonic survival and teratogenicity toxicity test, Federal Register Method 1001.0, is well suited for use with amphibians and is listed as a recommended procedure for use in ecological risk assessment. This study offers strong support for the inclusion of amphibians into the development of regulatory strategies for terrestrial and aquatic resources, protective criteria for aquatic life, and risk assessment.
Key words: amphibians, toxicity testing, risk assessment, terata