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Definition of "Hot Spring" in the "Hot Springs Act" and "Therapeutic Hot Spring" in the "Guideline to the Mineral Spring Analysis Methods"
What is a hot spring?・・・The "Hot Springs Act" enacted in 1948 defines a hot spring as "hot water, mineral water, steam, or other gas (excluding natural gas composed mainly of hydrocarbons) that comes out of the ground and has the temperature or substances listed in the attached table".
Therefore, if the temperature at the time of emergence from the ground is 25℃ or higher, it is considered a hot spring. Even if the temperature is lower than 25℃, it is considered a hot spring if it contains one or more of the substances (one or more of the 19 items other than temperature) in the specified amount. Steam and gas are also considered hot springs if the conditions are met.
Definition of "Hot Spring" in the "Hot Springs Act"
１．When the temperature (the temperature when collected from hot spring source) reaches 25℃ or more, it is regarded as "Hot spring".
２．When it contains a specified amount of the substances (one or more of the following) even when the temperature is less than 25℃, it is regarded as "Hot spring".
What is a therapeutic hot spring?・・・In the "Guideline to the Mineral Spring Analysis Methods" defined by the Ministry of the Environment for the analysis of hot spring components, a hot spring (excluding steam and other gases) is defined as having the temperature or substance listed as one that "can be used especially for therapeutic purposes".
Generally speaking, the term "hot spring" refers to these "therapeutic hot springs" which were classified into 10 types in the 2014 revision of the law. However, hot springs that do not fulfill the requirements of a "therapeutic hot spring" are not given a "spring quality name" and in such cases, the "spring quality name" may be described as "Hot Springs under the Hot Springs Act" or "Other Hot Springs".
Definition of "Therapeutic Hot Spring" in the "Guideline to the Mineral Spring Analysis Methods"
１．When the temperature (the temperature when collected from hot spring source)
reaches 25℃ or more, it is regarded as "Therapeutic hot spring".
２．When it contains a specified amount of the 7 substances (one or more of the following) even when the temperature is less than 25℃, it is regarded as "Therapeutic hot spring".
20 qualifications for "Hot spring" and 8 qualifications for "Therapeutic hot spring"
| Conditions/Components (contained amount in 1kg) ※If even one of the conditions is cleared, it is a "Hot spring" or "Therapeutic hot spring" |
A【Hot Springs Act】 Conditions of the "Hot spring" |
B【Guideline to the Mineral Spring Analysis Methods】 Conditions of the "Therapeutic hot spring" |
|
|---|---|---|---|
| 1 | Temperature (when collected from source) | 25℃ or more | |
| 2 | Dissolved Substances (excluding gaseous) | Total amount 1,000mg or more | |
| 3 | Free Carbon Dioxide (CO2) | 250mg or more | 1000mg or more (Carbon dioxide springs) |
| 4 | Lithium Ion (Li+) | 1mg or more | ― |
| 5 | Strontium Ion (Sr2+) | 10mg or more | ― |
| 6 | Barium Ion (Ba2+) | 5mg or more | ― |
| 7 | Total Iron Ion [Fe2+(Iron(Ⅱ) Ferro Ion)+Fe3+(Iron(Ⅲ) Ferri Ion)] | 10mg or more | 20mg or more (Iron containing springs) |
| 8 | First Manganese Ion (Mn2+) | 10mg or more | ― |
| 9 | Hydrogen Ion (H+) | 1mg or more | 1mg or more (Acidic springs) |
| 10 | Bromine Ion (Br-) | 5mg or more | ― |
| 11 | Iodide Ion (I-) | 1mg or more | 10mg or more (Iodine containing springs) |
| 12 | Fluoride Ion (F-) | 2mg or more | ― |
| 13 | Hydro Arsenate Ion (HAsO42-) | 1.3mg or more | ― |
| 14 | Meta-arsenic Acid (HAsO2) | 1mg or more | ― |
| 15 | Total sulfur (S) [HS-(Hydrogen Sulfide Ion)+ S2O32-(Thiosulfate Ion)+ H2S(Free Hydrogen Sulfide)] | 1mg or more | 2mg or more (Sulfur springs) |
| 16 | Metaboric Acid (HBO2) | 5mg or more | ― |
| 17 | Metasilicic Acid (H2SiO3) | 50mg or more | ― |
| 18 | Sodium Hydrogen Carbonate (Sodium Bicarbonate) (NaHCO3) | 340mg or more | ― |
| 19 | Radon (Rn) | 2 nanocuries or more 20×10-10Ci (curie) or more 20 (2 billionths of a curie) or more =74Bq (becquerel) / 5.5 mache or more |
3 nanocuries or more (Radioactive springs) 30×10-10Ci (curie) or more 30 (10 billionths of a curie) or more =111Bq (becquerel) / 8.25 mache or more |
| 20 | Radium Salt (as Ra) | 10-8mg or more 1/100 million mg or more |
― |
As shown in the table above, the conditions for qualification as a "therapeutic hot spring" are more stringent than those for qualification as a "hot spring". Only "therapeutic hot spring" is given a "spring quality name" (10 types). In addition, "indications" (efficacy) are approved for "therapeutic hot spring".
