[O-08] Poster presentations by senior high school students

[O08-P90] Comparison of water in the Amami Islands based on geological factors

*Mina Arimura¹, Miu Matsui¹, Koharu Miyashita¹ (1.Yoron High School)

Keywords:water hardness, ICP-AES, Amami Islands, tap water, health

Yoron Island is formed by uplifted coral reefs, lacking mountains or rivers, and relies on groundwater for drinking water, resulting in very high water hardness. Many residents purchase mineral water for drinking, and there is widespread concern about the health effects of tap water in Yoron Island. In this study, we measured the concentrations of Ca, Mg, and Na in raw water and drinking water at multiple locations in the Amami Islands. Additionally, we discussed the relationship between water quality and its impact on health based on the "K index" as proposed by Hashimoto (1988).Water hardness in Amami Oshima were below the Japanese average, while those in Kikai Island, Okinoerabu Island, and Yoron Island, composed of limestone, exceeded it. Furthermore, according to the K index, tap water in Yoron Island, Okinoerabu Island, and Kikai Island were classified as "healthy water". In the presentation, we will discuss these findings considering geological factors.