In order to examine the influence of coal ash disposed into the sea on the surrounding environments, some fundamental tests on the solution alkalized by coal ash were carried out in the laboratory.
　In these tests fly ash was adopted as a representative of coal ash, and the change of pH-value of the solution was investigated under such conditions as diluted by sea water, disposed in air, or filtered through sand. At the same time, the permeability of fly ash was evaluated. The results are as follows;
1. The effect of dilution by sea water on the pH-value has been clarified.
2. Carbon dioxide in air decreases the pH-value. So, this effect must be taken into account in some experiments in laboratory.
3. Filtering through sand decrease the pH-value, though not infinitely.
4. The coefficient of permeability of fly ash has been evaluated, which shows a tendency to decrease with time in sea water.