A century-old hot spring hotel in Japan has not changed its water for half a year! How to take a hot spring bath in a healthy way?

A century-old hot spring hotel in Japan was exposed to not changing the water for half a year! How to take a hot spring bath in a healthy way? Do you know what kind of water can be called hot spring? How can ordinary citizens distinguish fake hot springs?

Written by reporter Zhao Tianyu, Photo and text editor Chen Yongjie

New Media Editor/Lv Bingxin

Interview experts:

Gao Jianwei (Senior Engineer, Physical Geological Data Center, China Geological Survey)

Zheng Kexuan (Director of the Expert Committee of China Geothermal Industry Working Committee)

Cheng Jiqun (Deputy Chief Physician, Department of Dermatology, Third Medical Center, PLA General Hospital)

Recently, a century-old hot spring hotel in Japan became a hot topic on Weibo because it was revealed that the water had not been changed for half a year.

According to CCTV Finance, a scandal recently broke out at a century-old hot spring hotel in Japan. It turned out that the hot spring water in this time-honored hotel, which should have been changed once a week, was only changed once every six months, causing the Legionella bacteria to exceed the standard by 3,700 times, and some guests had already been infected and sought medical treatment.

Hot springs are becoming more and more popular nowadays. They can not only relieve physical fatigue, but also relieve mental stress. Especially for people living and working in cities, it is a good way to relax and maintain health. However, with the "generalization" of the concept of hot springs, some fake hot springs have begun to confuse people and fill in the gaps, causing considerable losses to consumers. What kind of water can be called hot springs? How to identify "fake hot springs"? What precautions should ordinary people take when taking hot springs?

Explore:

What is "hot spring water"?

What exactly is a "hot spring"? In fact, there is no authoritative, official definition of "hot spring" in my country so far.

Gao Jianwei, senior engineer of the Physical Geological Data Center of the China Geological Survey, told reporters that hot springs are a valuable and multi-purpose hydrothermal geothermal resource. Only mineral water that gushes out naturally from underground holes or cracks, exceeds 25°C (or the spring mouth is 5°C higher than the local average temperature), and contains trace elements that are beneficial to human health can be called hot spring water.

The causes of hot springs vary depending on the natural environment and geological conditions. In simple terms, they can be divided into two categories: one is sulfur hot spring water formed by magma (or volcanic activity) inside the earth's crust, and the other is carbonate hot spring water formed by surface water seeping into the strata. However, the formation of these two types of hot springs has prerequisites: there must be geothermal heat in order for hot springs to be produced.

Gao Jianwei explained that due to plate movement, tectonic and magmatic activities (including volcanic eruptions) are more frequent in some places. If the movement of the crustal plates causes the surface to rise, and there is uncooled magma below, it will continuously release heat and become a heat source. At this time, if there are water-bearing rock layers in the nearby pores, the heated water will surge up and form hot springs. This kind of hot spring mostly appears in areas with more intense geological movements. The Yangbajing Hot Spring in Tibet, located on the Qinghai-Tibet Plateau, is a typical example.

The other is the hot spring formed by the infiltration and circulation of surface water. The principle is that in some areas, surface water such as rainwater seeps down into the aquifer inside the earth's crust, and then forms groundwater. The groundwater is heated by the geothermal heat below and becomes hot water. If there is a dense and airtight rock layer above the groundwater, the groundwater and gas will be "locked" inside, and the pressure will increase. Once cracks appear in the rock layer above, the groundwater will gush out.

Because a larger hydrostatic pressure difference is required, this type of hot spring is more common in valleys. For example, Chengde City, Hebei Province, located in the valley of the Yanshan Mountains, was also called "Rehe" in the past because of its rich geothermal thermal resources.

▲Schematic diagram of hot spring formation (Drawing: Wang Xueying)

However, in recent years, with the large-scale development of tourism, the concept of hot springs has long been generalized. Zheng Kexin, director of the Expert Committee of the China Geothermal Industry Working Committee, pointed out that in addition to naturally flowing hot spring water, geothermal water with a water temperature above 25°C extracted through underground wells and geothermal water that is heated and pressurized at the water outlet are all called hot spring water.

It is precisely in this general context of generalized standards that the current hot spring industry has become a mixed bag. Coupled with the uneven distribution of my country's geothermal resources, there are even "fake hot springs" that are used to fill in the gaps, turning "hot spring bathing" into "expensive bathing", which has lost its meaning.

Anti-counterfeiting:

How to identify the fake hot springs

In addition to natural hot springs, there are many artificial hot springs in China. Hot spring water is extracted from deep fault zones by drilling wells. Zheng Kexuan said that this kind of hot spring is also called a hot spring well. The water temperature can reach above 25℃. Because it is artificially mined, it cannot be called a natural hot spring, but can only be called a "hot spring" or "artificial hot spring".

However, the outlet temperatures of many hot spring wells are relatively low, and the water temperature loss is large during the transportation of hot springs, which cannot meet the requirements of customers. It is necessary to use a heat exchanger to keep the water warm, that is, to heat it during the transportation process or at the outlet. This kind of hot spring is called a heated hot spring, which is an artificial method to make up for the temperature loss.

As long as the outlet water temperature and trace elements meet the standards, hot springs that only undergo heat exchange but not water exchange can be considered qualified. However, some behaviors that make a fuss about the "water" are naked "fake products".

Gao Jianwei said that some hot spring water comes from the surface, and is "heated" along the underground pipes before returning to the surface, giving people the illusion of underground hot spring water; in some areas where there is insufficient groundwater, the hot spring water is repeatedly heated and recycled. This kind of hot spring is very impure and very different from naturally formed hot springs, and the effect is greatly reduced.

What's worse, some scenic spots or businesses that don't have hot spring conditions at all, in order to attract consumers, add sulfur powder to artificial hot water to impersonate hot spring water, in order to make it look real. According to people familiar with the matter, the price of sulfur powder is not high, only 4-6 yuan per catty, but the hot spring water made from 1 catty of sulfur powder is enough for a 40-square-meter pool, which can be regarded as a "high-yield product."

In the eyes of many consumers, the greatest charm of hot springs is their therapeutic effects. Therefore, hot spring companies spare no expense in advertising. "It contains a variety of minerals and trace elements that are beneficial to the human body, it can improve beauty, strengthen the body, and treat arthritis and skin diseases..."

How can ordinary consumers distinguish between real and fake hot spring water? Zheng Kexuan said that the simplest way is to judge by the state after soaking: real hot spring water comes from deep underground, contains a lot of sodium, and is soft water. People can feel a slight buoyancy during soaking, and the skin feels slippery after soaking. On the contrary, fake hot spring water is hard water, mainly composed of calcium, and the skin will turn white and wrinkles after soaking.

The authenticity of hot springs can also be distinguished by region. Data show that my country's hot springs are mainly distributed in Tibet, Yunnan, Taiwan, Guangdong and Fujian, accounting for more than 50% of the total number of hot springs in the country, followed by Liaoning, Shandong, Jiangxi, Hunan, Hubei and Sichuan. Geothermal resources are mainly distributed in tectonic activity zones and large sedimentary basins. The former has relatively concentrated resources, such as Tibet, Yunnan, Sichuan, the southeastern coastal zone and the Liaodong-Jiaodong zone; the latter has a wide distribution of resources, such as the Beijing-Tianjin-Tangshan region in the North China Basin. "Geothermal resources in Northwest my country, the Loess Plateau, the Huanghuai region and the Yangtze River Delta are not abundant, especially the Loess Plateau," said Gao Jianwei.

Pay attention to health:

Who is not suitable for hot spring bathing?

Many people like to soak in hot springs for most of the day, but they don’t realize that this may lead to “overdoing it” and even physical discomfort, resulting in “hot spring disease.”

In fact, hot springs can be divided into acidic springs, alkaline springs and neutral springs according to the different ingredients in the water: acidic springs can promote blood circulation, improve blood vessel function, and have a certain bactericidal effect, but they are not suitable for patients with kidney disease and people with poor gastrointestinal function. Alkaline springs have a certain effect on skin diseases, rheumatism, and arthritis, but the "side effects" are also more obvious. They are not very friendly to people with skin allergies and are prone to "overexertion".

Especially sulfur hot springs, which are the most common among alkaline springs, Cheng Jiqun, deputy chief physician of the Dermatology Department of the Third Medical Center of the PLA General Hospital, told reporters that if you soak in sulfur hot springs for too long, the sulfur component can easily irritate the skin. In addition, there are not many natural hot springs around big cities, and artificial sulfur hot springs can easily dry out the skin. If you keep scrubbing, the skin's protective layer will be severely damaged, and it will become even drier and itchier.

"Even some people with poor skin conditions, such as those who are prone to allergies, will suffer from dry dermatitis. Scratching the skin can easily cause infection and cause rashes, leading to folliculitis. This type of patient is relatively common in clinical practice," said Cheng Jiqun.

Some people may experience chest tightness, palpitations, shortness of breath, dizziness and other symptoms due to the high water temperature and accelerated blood circulation, and even cause some patients with cardiovascular diseases to have high blood pressure, causing physical discomfort in a short period of time. Cheng Jiqun suggested that patients in the acute stage of various diseases, patients with basic skin diseases, elderly people with chronic diseases such as hypertension, diabetes, heart disease, and underage children are not suitable for hot springs.

"Especially in the northern regions, the climate is relatively dry in winter, and ordinary people can easily develop skin diseases if they soak in hot springs for a long time. We still have to follow the principle of moderation and keep moisturizing after soaking in hot springs. If conditions permit, try to go to high-star hot spring clubs, or hot springs with better hygiene conditions and water quality, which can also reduce the probability of 'hot spring disease'." Cheng Jiqun said.

Produced by: Science Central Kitchen

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