Okudogo No. 4-1 Gensen
Analysis UnverifiedOkudogo No. 4-1 Gensen is drawn from the gorge upstream along the Ishite River from Dogo's historic spa town. Its lukewarm 38.7°C water is alkaline at pH 9.4 and pairs hydrosulfide ions with radon, an uncommon combination. A faint sulfur scent and slippery feel suit bathers who like long, unhurried soaks to the sound of the stream.
The bar length shows how abundant each component is compared to thresholds that make it "distinctive" (therapeutic spring standards, beauty spring criteria, etc.).
A rare radioactive spring where trace radiation absorbed via inhalation and skin is expected to stimulate cells (the "hormesis effect").
Mild antibacterial action keeps the skin clean. Trace transdermal absorption supports tooth and bone health.
Scores are calculated from mineral analysis data based on the Mineral Spring Analysis Guidelines (Ministry of Environment, Japan). They are unrelated to facility atmosphere or service quality.
▸Note
The temperature, pH and component values shown here are based on the hot spring analysis (source). Actual values in the bath may differ depending on heating, dilution, recycling and filtration. Please check current usage status at the facility.
The source is a lukewarm 38.7°C, so warmed baths invite a longer soak. At pH 9.4 the water lifts away skin oils, so moisturize after bathing.
With 117.9 Bq/kg of radon and 3.8 mg/kg of hydrosulfide, this mild spring is traditionally associated with pain relief and may support immune system stimulation during a long, lukewarm soak.
The water is mild, but avoid bathing when unwell or after drinking alcohol, and take care not to overstay in the bath.
※ See the analysis data below for detailed contraindications
ANALYSIS DATAView all analysis fields ▼
Source Info
- Source name
- Okudogo No. 4-1 Gensen
- Spring type
- Sulfur-containing 弱放射能 Alkaline Simple Hot Spring
- Source temperature
- 38.7℃
- pH
- 9.4
- Osmotic pressure
- 低張性
Analysis Document
- Analysis date
- 2015-12-21
- Analyst organization
- 愛媛県立衛生環境研究所
- Registration No.
- 第1号
Cations
- Lithium ion Li⁺
- 0.40 mg/kg
- Sodium ion Na⁺
- 107 mg/kg
- Potassium ion K⁺
- 1.6 mg/kg
- Ammonium ion NH₄⁺
- 0.20 mg/kg
- Magnesium ion Mg²⁺
- < 0.1 mg/kg
- Calcium ion Ca²⁺
- 3.3 mg/kg
- Aluminum ion Al³⁺
- 0.05 mg/kg
- Manganese ion Mn²⁺
- < 0.005 mg/kg
- Iron(II) ion Fe²⁺
- < 0.05 mg/kg
- Iron(III) ion Fe³⁺
- < 0.05 mg/kg
- Zinc ion Zn²⁺
- < 0.005 mg/kg
- Lead ion Pb²⁺
- < 0.001 mg/kg
- Strontium ion Sr²⁺
- < 0.05 mg/kg
- Barium ion Ba²⁺
- < 0.1 mg/kg
- Copper ion Cu²⁺
- < 0.005 mg/kg
- Cadmium ion Cd²⁺
- < 0.0005 mg/kg
- Total cations
- 0.11 mg/kg
Anions
- Fluoride ion F⁻
- 15.5 mg/kg
- Chloride ion Cl⁻
- 89.6 mg/kg
- Hydroxide ion OH⁻
- 0.40 mg/kg
- Hydrogen sulfide ion HS⁻
- 3.8 mg/kg
- Thiosulfate ion S₂O₃²⁻
- < 0.1 mg/kg
- Sulfate ion SO₄²⁻
- 8.9 mg/kg
- Bicarbonate ion HCO₃⁻
- 45.5 mg/kg
- Carbonate ion CO₃²⁻
- 8.3 mg/kg
- Bromide ion Br⁻
- 0.20 mg/kg
- Iodide ion I⁻
- < 0.1 mg/kg
- Nitrite ion NO₂⁻
- < 0.1 mg/kg
- Nitrate ion NO₃⁻
- < 0.1 mg/kg
- Phosphate ion PO₄³⁻
- < 0.1 mg/kg
- Metaborate ion BO₂⁻
- 11.5 mg/kg
- Total anions
- 0.18 mg/kg
Undissociated Components
- Metasilicic acid H₂SiO₃
- 54.3 mg/kg
- Total undissociated
- 0.05 mg/kg
Dissolved Gas
- Total dissolved gas
- 0.00 mg/kg
Trace Components
- Radon Rn
- 117.9 Bq/kg
Totals
- Total dissolved substances
- 0.35 mg/kg
- Component total
- 0.35 mg/kg
Usage
- Heating
- Yes（浴場の掲示「成分に影響を与える項目」に『源泉の温度が低いため、入浴に適した温度に保つため加温しています』。最も加工の少ない大露天風呂のかけ流し浴槽（大湯・三寿の湯）も加温かけ流し（2025年12月の入湯記）。）
- Dilution
- No
- Recycle / Filter
- No
- Additives
- No
- Disinfection
- No
Indications & Contraindications
- Bathing indications
- Atopic dermatitis, Plaque psoriasis, Chronic eczema, Epidermal suppuration, Hyperuricemia (gout), Rheumatoid arthritis, Ankylosing spondylitis, Autonomic instability, Insomnia, Depression
- General indications
- High blood pressure (mild), Chronic pain or stiffness in muscles and joints, Muscle stiffness due to motor paralysis, Gastrointestinal dysfunction
- Contraindications
- Acute illness (especially with fever), Active tuberculosis, Malignant tumors, Severe heart disease, Respiratory failure, Renal failure, Bleeding disorders, Severe anemia, Any actively progressing illness, Pregnancy (especially early and late stages), Severe chronic dermatitis (sulphur springs), Undergoing radiation therapy, pregnancy (radioactive springs)
Drinking
- Drinkability
- Not drinkable