Abstract
The water quality of a brackishe lake (the Kasumigaura) was investigated at the flesch-water areas wherein rivers polluted by industrial waste and domestic sewage flowed. The sampling stations were settled at one point in every six rivers and eight points of the lake (as shown in Fig. 1). The following results were obtained. 1. In the rivers flowing through cities and towns, water qualities were influenced by the amount of rainfall on the sampling day. 2. BOD loading of the river polluted by industrial waste and domestic sewage was increased in summer. 3. The contamination of lake water near to the lake side was consequent on flow of polluted river water. These polluting substances were diffused with windows or waves.
