Abstract
Lake Izunuma is a famous place for the coming of migrating flying swans. But, the leftovers of foods which were fed to the waterbirds and their droppings are one of the causes of water pollution.
In order to prevent water pollution of Lake Izunuma, a feeding pond was constructed near the lake. Last winter, a total number of about 160, 000 waterbirds entered into this pond anda build-up of pollutants of 12kg T-N, 1.5kg T-P and 120kg COD were found. This means that the pollutants going to Lake Izunuma were reduced.
After this, the polluted water in the feeding pond will be introduced into a plant field and purification by the plant, Zizania latifolia, which is a food for the swans, will be attempted.
