Abstract
The monitoring system for feeding rate of Daphnia magna as fluorescent intensity of Chlorella vulgaris was constructed to evaluate toxicities. When 30 daphnids were added to water samples and run the system, the change of the feeding rate by time was measured accuracy. This method revealed that when the toxicants which were potassium dichromate, lead (II) nitrate, Triton X-100, and Benthiocarb were high concentration, the feeding rate decreased compare to the control after 180 minutes exposure. The feeding rate tended to increase linearly after 60 minutes exposure to all toxicants. With low concentrations of toxicants, lead (II) nitrate, Triton X-100, and Benthiocarb, the feeding rate difference 60 minutes exposure and 180 minutes exposure were larger than control. Thus, it was shown that the feeding rate didn't always decrease when toxicants coexisted in low concentration. This method had higher sensitivity than that of acute immobilization test on some toxicants. From these results, it was shown that this system can measure the change of feeding rate. Although it is necessary to improve the sensitivity, conditions, and construction of the system, the toxicity test based on this theory will be used effectively.
