Impact of Volcanic Ash from the 2016 Eruption of Mount Aso on the Water Quality of Rivers in Oita

Abstract

　This study aims to confirm the impact of volcanic ash by concentration and pollutant loading in river waters. The eruption of Mount Aso occurred in 2016. The concentration of Al increased after the eruption. The effect of volcanic ash disappeared 2 months after the eruption. For the pollutant loading, the effect of volcanic ash appeared 2 days after the eruption. The reason for the difference term has different the river flow. The reason for this difference was due to the differences in river flow. The percentage of the impact of volcanic ash was 0.3％. However, on the lowest flow rate condition, the percentage of the impact of volcanic ash became 5.3％.