PT13 Aquatic Ecotoxicology I
Exhibit Hall
8:00 AM - Tuesday
(PT206) Repeatability of toxicity tests with glochidia of freshwater mussels and influence of test organism ages.
Wang, N.1, Ingersoll, C.1, Greer, E.1, Whites, D.1, Dwyer, J.2, Roberts, A.2, Augspurger, T.3, Kane, C.4, Neves, R.5, Barnhart, C.6, 1 USGS, Columbia, MO2 USFWS, Columbia, MO3 USFWS, Raleigh, NC4 USFWS, Gloucester, VA5 USGS, Blacksburg, VA6 Southwest Missouri State University, Springfield, MO
ABSTRACT- A joint research project has been conducted to develop standardized guidance for conducting toxicity tests with glochidia of freshwater mussels. Previous studies have indicated that the toxicity tests with glochidia of many freshwater mussels could be conducted for 24 or 48 h with a control survival of over 90%. The present study evaluated the repeatability of toxicity tests within and between seasons using glochidia of two mussel species (mucket, Actinonaias ligamentina; fatmucket, Lampsilis siliquoidea) and three reference toxicants (copper, ammonia, and chlorine). The influence of glochidia ages was also evaluated to determine if organisms become more sensitive with time after isolation from female mussels. Toxicity tests (n=4 per toxicant for each species) were conducted for 6, 24, and 48 h under similar test conditions during spring and summer of 2003 and 2004. The variability of EC50s for all three toxicants, expressed as the coefficient of variation, ranged between 13 and 36% for mucket and between 17 and 33% for fatmucket. The EC50s for toxicants in tests started with 2- to 3-d old glochidia of mucket were frequently 20 to 40% lower than the EC50s for tests started with newly-isolated glochidia (>90% survival for 4 days in control water). In contrast, EC50s for fatmucket were similar when tests were started with either newly-isolated or 2-d old glochidia (>90% control survival for 5 days). Results of these studies indicated that toxicity tests with glochidia can be reproduced within a laboratory; however, ages of organisms used to start the tests may influence test results.
Key words: mussel, unionids, glochidia, toxicity test