Aquatic Invertebrates in Tolerance Investigations from Aristotle to Naumann

The earliest use of aquatic invertebrates in tolerance research was carried out to answer questions concerning adaptation and evolution somewhat over a century and a half ago. The procedures were essentially the same as those we use today for bioassays in the determination of water quality. In the first studies that have been reported, freshwater invertebrates were subjected to seawater, and marine invertebrates were exposed to freshwater. Later, many workers carried out research on the effects of ions in various combinations and concentrations on both freshwater and marine invertebrates. Some investigators were interested in the actions of drugs. It was only about five decades ago that serious consideration was first given to the use of aquatic invertebrates as test animals for the determination of the toxicity of potential pollutants. The author reviews representative reports of tolerance studies in which aquatic invertebrates were employed as experimental animals up through the time of Naumann. This is followed by a brief exposition of the author's procedures using Daphnia magna as the test animal in the determination of apparent thresholds of toxicity.