What Exactly is Thermal Water?
Thermal water is naturally heated groundwater that emerges from the earth's surface with a temperature above 20°C. During its long journey through subterranean rock formations, the water absorbs various minerals and trace elements, which gives each spring a unique chemical composition. This mineral-rich composition is the basis for many of the purported therapeutic benefits associated with thermal springs, a practice known as balneotherapy, which has existed for thousands of years. However, the same geological processes that enrich the water with beneficial minerals can also introduce dangerous contaminants.
The Allure of Drinking Thermal Water
Historically, and in some medically supervised contexts today, drinking thermal water has been part of a therapeutic regimen known as a "drinking cure". These cures are used to treat conditions affecting the gastrointestinal tract, liver, and kidneys, often capitalizing on the water's diuretic and detoxifying effects. For example, certain bicarbonate thermal waters are used to aid digestion and liver function. Similarly, waters with Glauber's salt are sometimes consumed to assist with metabolism. The perceived benefits come from the specific mineral profile of a particular spring, not from thermal water in general.
The Serious Risks of Drinking Untreated Thermal Water
Despite the historical context, drinking untreated thermal water from natural hot springs is extremely dangerous and not recommended. The risks are two-fold: biological contamination and high concentrations of toxic minerals.
Biological Contaminants
Untreated thermal water can be a breeding ground for harmful microorganisms. Some of the most concerning include:
- Brain-Eating Amoeba (Naegleria fowleri): This organism, found in warm freshwater, can be deadly if the water is inhaled into the nasal passages. While rare, the risk is a severe hazard in natural hot springs.
- Other Pathogens: Bacteria like Legionella, Pseudomonas, and E. coli can thrive in these environments, especially in pools that are not regularly treated and monitored.
Toxic Mineral Concentrations
The same process that gives thermal water its mineral profile can concentrate toxic elements to dangerous levels. High levels of these substances can cause serious health problems if ingested over time. The most common toxic minerals include:
- Arsenic: Some thermal waters, such as those in Yellowstone National Park, have arsenic levels hundreds to thousands of times higher than safe drinking standards. Long-term exposure to arsenic is linked to an increased risk of cancer and other chronic health issues.
- Fluoride: While fluoride is beneficial in small amounts, high concentrations found in some hydrothermal fluids can cause dental and skeletal fluorosis, a condition that damages bones and teeth.
- Mercury: This heavy metal can also accumulate in geothermal fluids and poses a significant risk to human health and wildlife in surrounding waterways.
Comparison of Thermal Water Sources
| Feature | Natural, Untreated Hot Spring | Regulated Spa or National Park Fountain |
|---|---|---|
| Purity | Not reliably pure. Prone to both biological and chemical contamination. | Monitored for safety. Often treated with filtration or ozone to meet drinking water standards. |
| Mineral Content | Varies widely and unpredictably by location. Can contain toxic elements like arsenic and fluoride. | Known and controlled mineral composition. Water intended for drinking is tested for purity. |
| Pathogens | High risk of dangerous microorganisms like Naegleria fowleri and E. coli. | Minimal risk due to regular testing and treatment processes. |
| Safety | Extremely hazardous to drink. Do not consume. | Safe to drink when explicitly designated for consumption by park or spa officials. |
Official Guidelines and Common Sense Precautions
For your safety, adhere to these guidelines regarding thermal water consumption:
- Drink Only from Approved Sources: Only consume thermal water from a dedicated drinking fountain in a regulated resort or national park, like Hot Springs National Park, where the water is professionally treated and monitored for safety.
- Never Drink Wild Spring Water: Never consume water from a wild or natural hot spring. The risk of chemical toxicity or dangerous microbial contamination is too high.
- Heed Warnings: Always observe posted signs. If a sign warns against drinking or touching the water, it is for your safety. Serious and even fatal accidents have occurred when visitors ignored these warnings.
- Consult a Professional for Cures: If considering a thermal water drinking cure, do so only under the strict supervision of a medical professional, and only with water from a regulated source with a known mineral profile.
The Final Verdict
While thermal water can offer benefits when used externally or when consumed under strictly controlled and monitored conditions, the overwhelming majority of natural thermal sources are not safe for drinking. The potential for dangerous biological pathogens and high concentrations of toxic minerals makes consuming untreated thermal water a significant health hazard. It is crucial to distinguish between medically sanctioned "drinking cures" at regulated spa facilities and the hazardous practice of drinking from a wild hot spring. When in doubt, always err on the side of caution: do not drink the water unless a reputable authority confirms it is safe and has been properly treated.
Conclusion
In conclusion, the decision to drink thermal water must be guided by sound scientific understanding and extreme caution. While the promise of mineral-rich water is appealing, the reality is that the risks from biological and chemical contamination in untreated sources are substantial and potentially life-threatening. The historical tradition of using thermal water for healing is valid only within the context of medically regulated spa settings with professionally treated water. For all other encounters, particularly with wild or unmonitored hot springs, the water is not for consumption. By following official safety guidelines and prioritizing caution, you can enjoy the other benefits of thermal water, such as soaking in regulated pools, without risking your health.
Note: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before beginning any new health regimen.
You can read more about the environmental impacts of geothermal activity on the NIWA website
