[O-07] Poster presentations by senior high school students

[O07-P72] Mechanism of how the Shirata river looks blue

*Shuhei Sugai¹, *Ryosuke Yoshida¹ (1.Shimoda high school)

Keywords:Shirata River, Izu Peninsula, sulfur, colloid, water

The Izu Peninsula, which faces Suruga Bay on the east side and Sagami Bay on the west side, is located at the eastern end of Shizuoka Prefecture. The Shirata River flows through the Izu Peninsula, and there was a sulfur mining trace upstream. We began our research with an interest in the pale-blue-looking points downstream, and eventually verified the sulfur production and also conducted a water quality survey of the surrounding area. At the site, pH was measured at each point of the mainstream and tributaries of Shirata River. We brought back the clay from the sulfur mining trace, and our analysis showed that the sulfer was contained 30% of the mass of the clay. The Shirata River, which supports the water supply in Higashiizu Town, was also the place that caused the oldest pollution in Japan from the Edo period to the Meiji period. We need to know more the Sirata River in order to coexist with peace of mind.