Development of methodology for community level toxicity testing using the fathead minnow seven day survival-growth impairment test

Abstract

Single species toxicity tests are widely used to assess the potential effects of a toxicant on aquatic life. Increasingly, it is necessary to understand how the results of these tests relate to toxicant effects in natural communities. This dissertation presents the methodology and validation for a community level toxicity test that bridges the gap between single species tests and natural community responses. The research involved control of environmental parameters, improvement of feeding regimes and testing of the final community. The results are presented as four separate papers.

The first paper addresses the development and validation of a standardized reconstituted water for culturing and toxicity testing of algae, cladocerans, a rotifer and two fish species. The next two papers address the substitution of the food source currently used in the fathead minnow survival-growth impairment test (<i>Artemia</i>) with a freshwater food source (the rotiter, <i>Brachionus calyciflorus</i>). Along with the alga <i>Chlorella vulgaris</i> (producer), B. calyciflorus (primary consumer) and the fathead minnow larvae (secondary consumer) comprise a three level food chain that was used to address trophic level interactions (feeding reduction and growth impairment) in the final phase of this research. The end result is an experimental procedure in which environmental parameters (water quality, temperature, etc.) and trophic structure parameters (Le. producer and primary consumer density) can be controlled well enough to insure that any shifts in community structure can be attributed to toxicant related effects.