(Report on Radiation in Europe) Development of Mining and the Use of Radiation in Bad Gastein

Hello, everyone. My name is Daichi, an expert providing the information about the radiation issues in an easy-to-understand manner.

In this and the next few articles, I would like to report on the use of radiation and environmental remediation efforts that I observed during my travels in Europe.

In this first article, I would like to introduce Bad Gastein, a town in central Austria that is well known as a historic spa resort.

In particular, I will report on my first-hand experience of visiting Gasteiner Heilstollen, where radon therapy is carried out in former mine tunnels.

In relation to this, I would also like to explain radon and the potential health effects of low-dose radiation exposure from radon.

In other words, this article will respond to the following questions:、

– What kind of town is Bad Gastein?
– In Bad Gastein, how is radiation used?
– How is low-dose radiation exposure considered to affect human health?

Table of contents of this article

I have been involved with the radiation-relevant issues, like the policy on the decontamination activities and the management of the Interim Storage Facility, after the accident of the Fukushima Daiichi Nuclear Power Plant in 2011.

I received a doctorate in the field of radiation, while working in Fukushima.

(Report on Radiation in Europe) Development of Mining and the Use of Radiation in Bad Gastein

First of all, I would like to provide some basic information about the trip, followed by the history of Bad Gastein, an overview of Gasteiner Heilstollen and my first-hand experience of the using the facility, and finally the potential health effects of low-dose radiation exposure from radon.

Introduction

This was my second visit to Bad Gastein, following my first visit in June 2021.

At that time, I knew nothing about the use of radiation in Bad Gastein and simply visited the town to see the famous spa resort on my way back from Großglockner, the highest mountain in Austria.

I later learned that Bad Gastein is a unique town in terms of the use of radiation, even from a global perspective, and decided to visit it again.

Itinerary and route

(Approximate locations of Vienna, Bad Hofgastein and Bad Gastein. For precise locations, please refer to a map.)

My itinerary and route for this trip were as follows:

Sunday, 22 March
– I departed from Vienna in the morning and changed trains at Salzburg Central Station. Normally, there are direct trains from Salzburg to Bad Gastein, but due to construction work, I had to get off the train partway through the journey and transfer to a replacement bus to Bad Gastein Station.
– After arriving in Bad Gastein, I left my luggage at the hotel and travelled to Bad Hofgastein by bus.
– I stayed at Alpentherme Gastein for a couple of hours.
– I went back to Bad Gastein and walked around the town.
– After dinner, I stayed at Felsentherme Bad Gastein for a couple of hours.
– I stayed in Bad Gastein overnight.

(Wien Hauptbahnhof)(Vienna Central Station)

Monday, 23 March
– In the morning, I took the cable car up to Stubnerkogel and and walked around near the summit.
– I went back to Bad Gastein and walked around the town again.
– In the afternoon, I relaxed at Felsentherme Bad Gastein.
– I stayed in Bad Gastein overnight.

Tuesday, 24 March
– After checking out, I took a bus to Gasteiner Heilstollen.
– After staying there for four or five hours, I returned to Bad Gastein and then continued on to Vienna.

Overview of Bad Gastein

In the following section, I will look at the history of Bad Gastein and its relationship with radiation.

History and development

(Bahnhof Bad Gastein)

Bad Gastein is a spa resort located in the State of Salzburg, Austria.

It is located in the heart of the Gastein Valley (Gasteinertal), surrounded by the Alps, and has long been known as a spa town.

Gold and silver were mined in this region from the Middle Ages onwards, and the area prospered greatly as a result of mining.

After that, the benefits of the hot springs became widely known, and in the 19th century, the area developed into one of Europe’s leading spa resorts.

And the area is also well known for having been visited by many members of royalty and the aristocracy, as well as prominent figures, including Austrian Emperor Franz Joseph I and German Emperor Wilhelm I.

Although some buildings have fallen into ruin, many magnificent hotels and spa facilities built between the late 19th and early 20th centuries still remain in the town, providing a glimpse of its former prosperity.

Characteristics as a spa resort

(Landscape of Bad Gastein)

The most distinctive feature of Bad Gastein is its unique landscape, shaped by its location in a steep-sided valley.

A large waterfall, the Gastein Waterfall (Gasteiner Wasserfall), flows through the centre of the town, with hotels and houses lining the slopes on both sides.

The region has abundant hot spring resources, and even today, many tourists visit for hot spring bathing and wellness.

In winter, the area is also popular as a ski resort, with convenient access to the Stubnerkogelbahn cable car, located very close to the station.

As a result, the area attracts tourists throughout the year.

(Stubnerkogelbahn)

In addition, as I will explain below, unlike typical spa resorts, one of the distinctive features of Bad Gastein is that it has not only hot springs but also a therapeutic facility that makes use of radon originating from former mine tunnels.

Relationship with radiation

Today, Bad Gastein is also well known as a spa resort for radon therapy, but its history began not with the use of radiation, but with its long tradition of hot spring bathing.

In the centre of the town, there is a stone monument describing the legend of the discovery of the hot springs.

I may not have transcribed it entirely accurately, but the following words appear to be inscribed on the monument:

Aus der Bad Gasteiner Quellensage
„Lasst uns dies Waldwundtier, dass es am Wunderborn gesunde, erzählt, was ihr entdeckt und bringt vom Heilquell allen Kunde.“

As this is an old and poetic expression, it is not easy to interpret precisely, but it can be understood roughly as follows:

“Let us tell how a wounded animal from the forest was healed by the miraculous spring, and let people know what you have discovered and what the healing spring has brought.”

The relief depicts several people and an animal and appears to represent the legend of the discovery of the hot spring and its healing effects.

The fact that this legend has been passed down to the present day suggests that the hot springs have long been regarded as something special by the local community.

(Stone monument describing the legend that a wounded animal from the forest was healed)

In fact, hot springs have been used in Bad Gastein for centuries, and in the 19th century, the town developed into one of Europe’s leading spa resorts.

According to the information board at the Thermalquellpark (Hot Spring Source Park), 23 thermal springs have been identified in Bad Gastein, 13 of which are currently in use, with a total flow of approximately 5 million litres per day.

The Elisabethquelle is still preserved in the centre of the town.

It is one of the main thermal springs, with a temperature of approximately 46°C and a flow of around 2,500 m³ per day, and plays an important role in supporting Bad Gastein’s present-day spa culture.

The information board also shows the radon concentration of each thermal spring, indicating that radon is regarded as one of the important characteristics of the hot springs in Bad Gastein.

(Elisabethquelle)

Radon, a naturally occurring radioactive gas, was discovered in 1900. In the early 20th century, it was subsequently found that radon was present in the thermal water and steam in Gastein, as well as in the air inside the mine tunnels.

Before that, people thought that the effects of the hot springs were mainly attributable to their heat and mineral content, but after the discovery of radiation, radon also began to attract attention as one of the characteristics of the hot springs.

As described above, the use of radiation in Bad Gastein developed on the foundation of this long-established spa culture.

One of the representative examples is Radon-Thermal-Dunstbad (radon thermal steam bath), located near the Elisabethquelle.

According to the official website, therapy using radon-containing thermal steam from the Elisabethquelle has been provided at this facility since 1825.

Even today, the thermal steam is channelled into the treatment rooms through a shaft system.

(Radon-Thermal-Dunstbad)

In addition, Felsentherme Bad Gastein is located directly in front of the station (“Felsen” means “rock” in German).

Felsentherme Bad Gastein is a large spa and wellness facility that is open to the general public, with several thermal pools, saunas and relaxation areas.

While Gasteiner Heilstollen, which I will explain later, and Radon-Thermal-Dunstbad, which I mentioned earlier, have a stronger focus on therapeutic treatment, Felsentherme Bad Gastein offers spa and wellness experiences to a wider range of visitors, with large thermal pools, saunas and other facilities.

(Felsentherme Bad Gastein)

I also visited a similar spa facility, Alpentherme Gastein, in the neighbouring town of Bad Hofgastein, approximately 7km from Bad Gastein.

Although both facilities mention radon on their websites, inside the facilities, the emphasis was on enjoying the thermal baths rather than on therapy or medical treatment.

(Alpentherme Gastein)

Interestingly, while walking around the town, I did not get the impression that the use of radiation was treated as something special or kept separate from everyday life.

Thermal springs, parks, steam bath facilities and spa facilities naturally coexist, and the use of radon is seen as a natural extension of this spa culture.

And the facility that can be seen as the culmination of this spa culture is Gasteiner Heilstollen, located approximately 10 km from the town.

After World War II, attention was drawn to the possibility of using the unique environment inside the mine tunnels for therapeutic purposes, and the site was opened as a therapeutic facility in 1952.

Today, it is well known around the world as a radon therapy facility, and I will explain it in more detail later.

Town today

(View near the summit after taking the Stubnerkogelbahn)

When I visited the town, I saw many tourists and people who had come for therapy.

In particular, I saw not only elderly visitors but also relatively young people and families, which gave me the impression that the town attracts a wide range of visitors as both a ski resort and a spa resort.

On the other hand, as I walked through the town, I also saw some large hotels that were no longer in use, reflecting the town’s former prosperity.

Bad Gastein developed into one of Europe’s leading spa resorts from the 19th to the early 20th century.

However, for a period after World War II, the town appears to have faced challenges such as a decline in the number of tourists and the closure of hotels, due to changes in travel styles, the growing popularity of international travel, and the decline of the culture of long-term stays for therapeutic purposes.

In recent years, however, efforts have been made to redevelop historic buildings, renovate hotels, and capture growing demand for tourism and wellness. In fact, I saw several buildings undergoing renovation in the town.

I could see efforts to revitalise the town as a tourist destination while maintaining its appeal as a traditional spa resort.

Overview of Gasteiner Heilstollen

In the following sections, I would like to explain the history and provide an overview of Gasteiner Heilstollen, which was the main destination of this trip, as well as share my first-hand experience of visiting the facility.

(Exterior of Gasteiner Heilstollen)

History of the facility

Gasteiner Heilstollen is a tunnel therapy facility located in the Böckstein district of Salzburg, Austria, approximately 10 km from the centre of Bad Gastein.

This tunnel was originally excavated for the development of a gold mine.

Gold and silver had been mined in the Gastein region since the Middle Ages.

The Paselstollen, which formed the basis of the present-day Gasteiner Heilstollen, was excavated between 1940 and 1944, but the expected mineral deposits were not found.

On the other hand, the tunnel had a unique environment with high temperatures and high humidity, and some of the miners involved in the excavation work began to report relief from joint pain and rheumatic symptoms.

Afterwards, medical investigations were conducted, and in the early 1950s, it was confirmed that the vapour inside the tunnel contained a high concentration of radon.

This led to further research and therapeutic use, and in 1952, Gasteiner Heilstollen began full-scale operation as a therapeutic facility.

Today, the facility attracts many people not only from Austria but also from Germany and other European countries for the treatment of conditions such as rheumatoid arthritis, ankylosing spondylitis, and chronic pain.

(Exhibition on the researchers and founders)

Overview of the facility

Gasteiner Heilstollen is a highly distinctive facility, even by international standards, offering therapy that combines a high-temperature, high-humidity environment with radon.

In Austria, it is classified not as a general hospital (Krankenhaus), but as an outpatient therapeutic facility (Kureinrichtung) using natural therapeutic resources (Heilvorkommen).

The Gastein Valley is a state-recognized health resort area (Kurort), and the Gasteiner Heilstollen is one of its principal facilities.

The facility comprises above-ground facilities, including a reception area, consultation rooms, waiting areas, and changing rooms, together with therapeutic areas located inside the tunnels.

For first-time visitors, a medical consultation is conducted to assess their health status and determine whether the treatment is appropriate for them.

Based on this assessment, an individualized therapeutic program is established.

However, as I did, members of the general public can also experience the facility by making a reservation in advance.

Under Austria’s public health insurance system, this therapy is recognized as a treatment for certain medical conditions and may be covered by health insurance if the relevant requirements are met.

Therefore, many people visit the facility on the recommendation of a doctor or with support from the health insurance system, and it functions as part of the medical and therapeutic care system rather than as a tourist facility.

One of the distinctive features of Gasteiner Heilstollen is that, despite using naturally occurring radon, it operates as a therapeutic facility integrated into Austria’s public health insurance system.

(Waiting area)

How to use the facility

Users undergo a medical examination in advance to confirm their health condition.

As I was using the facility on a trial basis, I also had to register online in advance.

First, I entered my preferred visit dates on the Gasteiner Heilstollen website arranged the date of my visit.

On the day of my therapy session, after checking in at reception, I watched an introductory video about the facility and had a medical consultation with a doctor.

I then changed into swimwear and a special bathrobe before attending another briefing for participants prior to entering the tunnel. (As the briefing was conducted in German, I could not fully understand everything that was explained.)

I attended a briefing for first-time visitors, along with around 20 other participants.

At the same time, I also saw many people who appeared to be regular visitors to the facility.

(Medical questionnaire and wristband with an embedded chip, worn inside the facility)

(Room where participants receive a briefing before entering the tunnel. I attended a briefing for first-time visitors in a separate room.)

After that, I boarded a special train and travelled approximately 2.5 km into the tunnel to the therapeutic area.

As the train was originally used in the mine tunnels, it was neither particularly large nor comfortable.

As the train travelled deeper and deeper into the tunnel, I could hear its rumbling sound echoing through the old mine tunnels and feel the temperature and humidity gradually increasing.

Of course, I assumed that adequate safety measures were in place, but at the same time, I couldn’t help feeling a slight sense of unease that, if the tunnel were to collapse, I might never make it out.

Inside the mine tunnel, there are several therapeutic stations (Liegestationen), where visitors lie on beds for a certain period of time.

The therapeutic area is divided into several zones with different temperatures and humidity levels.

It seems that visitors are assigned to a particular zone depending on their health conditions and treatment plans.

I got off the train at Station I, which had the lowest temperature and humidity, and lay on one of the beds there for about an hour.

(Stations along the dedicated train route (source: facility brochure). There are five stations, from Station I to Station IV, and both temperature and humidity tend to increase as the train travels deeper into the tunnel.)

(Visitors inside the tunnel (source: facility brochure). In reality, the tunnel is almost completely dark, and I also spent about an hour lying down in the hot and humid conditions.)

The main characteristics of the environment inside the tunnel are as follows:

– Temperature: Approximately 37–41°C
– Relative humidity: Approximately 70–100%
– Radon concentration: Approximately 40,000–160,000 Bq/m³

These environmental conditions occur naturally inside the tunnel and are not created by artificial heating.

After the treatment, visitors are advised to rest for a certain period of time in the designated rest area.

I also rested there for a while before leaving the facility.

As described above, the facility as a whole combines medical supervision with elements of relaxation and wellness.

Although I visited the facility only once to experience the treatment, a typical therapeutic programme recommends several to around a dozen sessions in the tunnel.

Repeated sessions are believed to help prolong the therapeutic effects.

Radiation protection measures

As naturally occurring radon is used for therapeutic purposes at Gasteiner Heilstollen, appropriate safety measures are implemented in accordance with the requirements for medical facilities.

Visitors undergo a medical examination by a doctor beforehand, and their suitability for the treatment is assessed based on factors such as their symptoms and medical history.

The number of treatment sessions and the intervals between them are also managed under the supervision of a doctor.

These measures are considered to be primarily intended to ensure the effectiveness and safety of the treatment, but they may also contribute to controlling radiation exposure from radon.

In addition, access to the facility is restricted for pregnant women and people with certain medical conditions.

When I visited the facility, no dosimeter was provided.

Therefore, I could not confirm how the radiation dose received by each visitor is assessed and managed.

However, it appeared that at least the number of treatment sessions and the duration of each session were controlled by the facility.

When I asked the doctor who conducted my medical examination about the radiation dose, he explained that it was comparable to the dose received during an X-ray examination.

Although I could not confirm the details of the methods used to assess radiation doses, the information provided suggested that the facility regarded the risks associated with radiation exposure as limited.

On the other hand, occupational exposure is managed for workers, including through the control of working hours inside the tunnel and the assessment of individual radiation doses.

Radiation protection for workers is considered particularly important because they may spend much longer periods of time inside the tunnel than visitors.

While radon is accepted as one of the natural elements of the therapeutic environment, systems are in place for medical assessment of suitability for treatment, management of treatment sessions, and control of occupational exposure.

This suggests that efforts are being made to balance the therapeutic use of radiation with radiation protection.

Overview of potential health effects of low-dose radiation exposure from radon

I would now like to discuss the potential health effects of low-dose radiation exposure from radon, from a scientific perspective.

What is radon?

Radon is a radioactive noble gas belonging to the uranium decay series and is one of the naturally occurring radioactive substances.

It has neither colour nor smell and is produced by the radioactive decay of radium contained in soil and rocks.

Radon was discovered by the German physicist Friedrich Ernst Dorn in 1900.

Dorn observed a previously unknown radioactive gas released from radium, which was initially called “radium emanation”.

It was later recognized as a distinct chemical element and eventually became known as “radon”.

Although radon itself is chemically inert, it is known that the lungs are exposed to radiation when radioactive decay products of radon (radon progeny) are inhaled.

Therefore, radon is recognized worldwide as one of the major contributors to natural radiation exposure. (For more details please also visit this article.)

Expected effects

Radon therapy has been reported to have several effects, including the suppression of inflammatory responses and effects on the immune system.

According to Gasteiner Heilstollen, radon therapy is expected to help relieve symptoms associated with conditions such as rheumatoid arthritis, ankylosing spondylitis, chronic pain and osteoarthritis.

Many people visit the facility seeking pain relief and an improved quality of life.

In addition, improved blood circulation and relaxation of muscle tension due to the hot and humid environment are also thought to contribute to the therapeutic effects.

However, the effects experienced by individuals vary, and it is not easy to fully distinguish the effects of radon itself from those of heat and other factors when evaluating the therapeutic benefits.

Current scientific knowledge

As mentioned earlier, radon therapy has been reported to have various therapeutic effects, and its effectiveness and underlying mechanisms have been studied for many years.

However, in the field of radiation protection, the linear no-threshold (LNT) model, which assumes that the risk of radiation-induced health effects increases in proportion to the radiation dose, even at low doses, forms the basis of the international system of radiological protection.

In addition, long-term exposure to high concentrations of radon is known to increase the risk of lung cancer, and the WHO and ICRP recommend reducing radon concentrations in homes and workplaces.

Therefore, radon therapy needs to be evaluated by considering both its expected benefits and potential risks.

Regulation and approaches in Europe

Radon is known to be associated with an increased risk of lung cancer, and the European Union’s Basic Safety Standards (BSS) Directive also requires measures to reduce radon concentrations in homes and workplaces.

In fact, radon mitigation is recognized as one of the important priorities in radiation protection across Europe.

On the other hand, in some Central European countries, such as Austria, Germany and the Czech Republic, facilities offering radon therapy are integrated into the healthcare and spa treatment systems.

As mentioned earlier, treatment at these facilities may also be covered by public health insurance.

Gasteiner Heilstollen is one such example, offering radon therapy subject to a doctor’s assessment of each patient’s suitability for treatment.

At least in Central Europe, a certain degree of social acceptance has developed over many years, supported by a long history of use and accumulated clinical experience.

In this context, Gasteiner Heilstollen can be regarded as an interesting case study when considering how to balance the therapeutic use of radiation with radiation protection.

Summary

実際に現地を訪れて感じたのは、バート・ガシュタインにおける放射線利用は単独の施設から始まったものではなく、数百年にわたる温泉文化の上に、20世紀以降の放射線利用が積み重なった結果であるということです。

町の中に点在する温泉源、スパ、ラドンを利用した療養施設などは、その歴史的な連続性を現在に伝えています。

町の中では「ラドン」や「放射線」を強く強調するような雰囲気はあまり感じられず、ラドンよりは温泉、ウェルネス、サウナ、リラクゼーションといった要素が前面に出されており、放射線利用は地域の温泉文化の一部として位置付けられているように感じられました。

ガシュタイナー・ハイルシュトーレンではラドンを利用した療養が行われていますが、施設内に過度な緊張感はなく、利用者もごく自然に療養を受けていました。

もちろん、ラドン療法の有効性や低線量放射線の健康影響については現在も研究が続いています。

LNTモデルも考慮すると、低線量の放射線が健康に良い影響を及ぼす可能性があるとしても、その効果はわずかなのかもしれません。

しかし今回の訪問を通じて感じたのは、放射線を無条件に受け入れることでも無条件に避けることでもなく、その利益とリスクを適切に評価した上で利用することの重要性と、温泉・保養文化を通じ、長い年月をかけて培ってきた、放射線が社会に受け入れられていくプロセスです。

日本にもラドンやラジウムを含む温泉が数多く存在しており、自然放射線を含む温泉を利用する文化は古くから存在しています。

そう考えると、放射線を日常生活の中で受け入れる素地そのものは、日本にも十分にあると思いますし、日本で環境中に存在する放射線について議論するときにも、こうした海外の事例を知ることには大きな意味があると感じました。

バート・ガシュタインの事例は、日本にそのまま適用できるものではありませんが、放射線と社会との関係は、科学だけで決まるものではなく、歴史や文化、地域社会の価値観とも深く関係していることを改めて実感しました。

You can read the same article in Japanese here.

Thank you very much for reading this article.

See you next time!