Mj. Beach et D. Pascoe, THE ROLE OF HYDRA-VULGARIS (PALLAS) IN ASSESSING THE TOXICITY OF FRESH-WATER POLLUTANTS, Water research, 32(1), 1998, pp. 101-106
The freshwater coelenterate Hydra vulgaris is an important component o
f freshwater ecosystems, and this study aimed to establish its value a
s an indicator of pollutants entering freshwater. The toxicity of the
heavy metals copper, cadmium and zinc was assessed using both acute le
thal and sub-lethal responses. Techniques involving the identification
and large-scale culture of Hydra were also examined. The acute lethal
toxicity of copper, cadmium and zinc was measured by determining 24-h
, 48-h, 72-h and 96-h LC50 values and the sub-lethal effects assessed
using a feeding test. The feeding test examined toxic effects on the n
ormal responses of Hydra to the presence of the prey provided, neonate
Daphnia magna (Strauss). Results of this study demonstrated that H. v
ulgaris (Pallas) is a suitable species for evaluating the toxicity of
freshwater pollutants and can be used successfully to rank toxicants i
n order of potential hazard. It can be cultured easily in the laborato
ry to provide large numbers of test animals and can be used in simple,
cost-effective bioassays of both acute and sub-acute toxicity. (C) 19
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