亀島川温泉
Kameshimagawa Onsen塩
Chloride
+ Bicarbonate
- Color
- brown and transparent
- Taste
- salty
- Odor
- not recorded
Sodium Chloride-Bicarbonate spring
pH 8.5AlkalineCold mineral source · 18°CHigh silicaCold mineral
Composition fingerprint3.8 g/kg dissolved · Hypotonic
Na⁺78
Mg²⁺14
Cl⁻75
HCO₃⁻22
◀ CationsAnions ▶
- Sodium Na⁺
- salt's cation — pairs with chloride to make the water salty.
- Chloride Cl⁻
- table-salt anion — coats the skin and holds heat in.
Known good for
- Warmingcold sensitivity
- Smooth skindry, rough skin
- Cutsminor wounds
Kameshimagawa Onsen is a sodium chloride-bicarbonate cold mineral spring drawn from beneath Shinkawa in central Tokyo. At 18.2 °C it is a cold-mineral source (below 25 °C) that is heated for bathing, and it arrives brown but clear, with a salty tang on the lips. Bicarbonate softness layers over the heat-retaining chloride base, and at pH 8.5 the water is alkaline with the slippery feel that places it in Japan's beauty-water family, helped along by 63.3 mg/kg of metasilicic acid. Moderately mineralized at 3,804 mg/kg of dissolved solids, it has noticeable body; the certificate's sample was taken from the source tank rather than at the wellhead.
Sampled at storage tank·Analyzed Dec 9, 2025·一般社団法人 長野県薬剤師会