| |
Communication at the NABS Annual meeting, Keystone, 2000
(34) CADMIUM BOUND TO DIATOM MAT SURFACES: ECOTOXICOLOGICAL RESPONSES OF THE MAYFLY BAETIS TRICAUDATUS.
E.C. Irving1, D.J. Baird1, and J.M. Culp2. 1Environment Group, Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, Scotland., 2National Water Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon, Saskatchewan, S7N 3H5, Canada.
The trophic uptake of metals and associated feeding and/or growth inhibition has been established for various aquatic invertebrates. In this study, we evaluated the responses of the mayfly Baetis tricaudatus to cadmium bound to the surface of diatom mats (Navicula pelliculosa). Both these species are ecologically important as they represent an important energy pathway to higher trophic levels. Laboratory feeding experiments were conducted using an artificial stream system. Cadmium was only present surface-bound to Navicula mats. Prior to feeding, mats were submerged in cadmium, with the amount bound being governed by the concentration of the solution. Feeding inhibition did not occur in any of the treatments during a 1-h feeding experiment. During a 13-d feeding experiment, feeding and growth inhibitions did occur in the highest cadmium exposure treatment. This exposure level was a realistic cadmium concentration for algal mats to accumulate in aquatic environments. Thus, when Baetis was exposed to realistic concentrations of dietary cadmium, feeding and growth inhibitions were evident. Conversely, when exposed to water-borne cadmium, Baetis proved to be very tolerant. In conclusion, the sub-lethal feeding and growth responses of Baetis tricaudatus to dietary exposure appear to be more sensitive than the standard lethal response to waterborne exposure.
Presented at 3:30 PM on Monday, May 29, 2000 in Bioassessment II
|
|
