Wanchamai Karntanut and David Pascoe

pp. 869 - 880

Abstract

The cnidarian Hydra has been widely used to assess the acute toxicity of freshwater pollutants, but very little is known about pollutant accumulation by this animal. The purpose of this study was to measure the accumulation of the three metals, i.e., copper, cadmium and zinc directly from water and also via its
prey and to relate the recorded tissue concentrations to any change in biological activities. It was found that copper, cadmium and zinc all were accumulated in the tissues of Hydra exposed directly to the metals in water and also those exposed indirectly through feeding on contaminated prey. The bioconcentration factor (BCF) recorded at 48 hours following direct uptake from water was greatest for copper (773), followed by cadmium (409) and zinc (125), although the greatest increase in body burden occurred with cadmium, Metal body burdens of Hydra fed on contaminated prey (Artemia) increased in the same metal sequence as for direct uptake from water and the increase was highest (250 times that of control Hydra) for cadmium; however, biomagnification factors (BMFs) were all < 1.0 indicating that there was little potential for increasing accumulation via the food chain. There was significant inhibition of regeneration and bud production in polyps which had fed on cadmium-containing Artemia but not on copper or zinc- containing Artemia.