PM02 Metals in the Environment: Aquatic Biological Perspectives
Exhibit Hall
8:00 AM - Monday, 10 November 2003
(PM032) Do metals reduce feeding?
SOFYAN, A1, BIRGE, WJ1, 2, 1 Department of Biology, University of Kentucky, Lexington, KY, USA2 Graduate Center forToxicology, University of Kentucky, Lexington, KY, USA
ABSTRACT- We investigated the effects of water column and dietary metals (i.e., cadmium, chromium, copper and silver) exposures on feeding inhibition on Ceriodaphnia dubia using the U.S. EPA three-brood test. Following a seven-day exposure, C. dubia feeding rates were greatly reduced dose dependently for both dietary and water column exposures. Cadmium observed to be the most influencing metal in reducing C. dubia feeding rate, followed by silver, copper and chromium. In the water column exposure experiment, cadmium significantly reduced feeding at 5 microgram/liter, whereas silver and copper significantly reduced feeding at 10 microgram/liter, and chromium significantly reduced feeding at 20 microgram/liter if compared to control. From dietary exposure experiment, cadmium significantly reduced feeding at a very low concentration (3.1 microgram/gram algal DW), whereas silver reduced feeding at 7.6 microgram/gram DW, followed by copper at 15.9 microgram/gram DW and chromium at 283.5 microgram/gram DW. These results showed that metals from water column and dietary routes of exposures reduced animal feeding by a similar fashion. These results also showed that C. dubia feeding rate was a sensitive endpoint for both water column and dietary metals exposures. Because food is an essential requirement for the animal, reduction on feeding could affect many important biological processes such as reproduction and survival. These studies suggest that both water column and dietary routes of metal exposures are important in producing toxicity on aquatic animals; therefore, both of them should be considered in developing the new regulatory criteria.
Key words: water column and dietary routes, metals, feeding, Ceriodaphnia dubia