From snow-capped volcanoes, to crater lakes, geysers, and natural springs, geothermal wonders are a part of Aotearoa’s splendid natural landscape, attracting thousands of tourists each year. Soaking in one of New Zealand’s thermal springs can be bliss and even improve your heath; soothing aches, boosting circulation, and even improving your skin. However, they can also be incredibly dangerous. Read on to learn about the lesser-known dangers of New Zealand’s thermal springs before your next visit.

Contents

1. How thermal springs are formed
2. The dangers of hot springs
3. Misadventure
4. Why you should never put your head underwater
5. Toxic gases
6. Conclusion
7. Top safety tips

How are hot springs formed?

Thermal springs are formed when rainwater seeps below bedrock to the earth’s thermal zone, where it is heated by magma. The heated water then bubbles to the surface to form a spring.

Beware: The Dangers of Thermal Springs

New Zealand’s thermal springs are accompanied by an array of dangers. Some, such as drowning, are obvious, but others like arsenic poisoning, are more insidious.

Misadventure

Drowning

Thermal springs in New Zealand have claimed a number of victims over the decades. The clear, benign-looking waters are often deceptively deep with boiling vents, submerged branches, and other snags.

Fainting

Some people are prone to fainting (orthostatic hypotension) after exiting a thermal pool. A lengthy soak in hot water lowers your blood pressure. Consequently, when you stand blood rushes to your lower body away from your head and heart, leading to ‘faintness’ (Mayo Clinic 2021). Fainting is more likely if you have heart problems, low blood pressure, are dehydrated, overheated, or taking certain medications.  

Don’t stray from safety
The ground around thermal springs may appear firm, but there have been cases where areas ‘off the main track’ have collapsed. For instance, the ankles of a bather at a natural spring were seriously burned after he unexpectedly plunged into boiling mud (Olley 2020).

Why you should never put your head underwater in thermal springs

Why? Naegleria fowleri is a thermophilic (heat-loving) amoeba/single-celled organism found in soil and freshwater. It can enter through your nasal passages and infect your brain. In some cases, an infection with N. fowleri leads to amoebic meningoencephalitis, a fatal disease that has no proven cure. Between 1968 and 2000, there have been nine fatalities caused by meningoencephalitis in New Zealand, although it is considered a rare condition.

Arsenic and toxic gases

Shockingly, tests have shown that the thermal pools around Taupō commonly used by bathers, have high levels of arsenic in its more toxic form, arsenite. Concentrations measured in several of these springs were high enough to be a potential risk to human health (Lord et al. 2012). In the past, inhalation of hydrogen sulphide poisoning (H₂S) has also caused fatalities. Two men died from H₂S poisoning in Rotorua between 2007 and 2008 (Bassindale and Hosking 2011).

Conclusion: New Zealand’s thermal springs

A visit to the thermal pools does wonders for calming the body and mind. These pools have been used for hundreds of years by Māori, and are an integral part of Aotearoa’s history, culture, and geothermal landscape. However, the volatile nature of New Zealand’s thermal springs means that a degree of risk is always involved. Interested in reading more essential New Zealand travel tips? Click here.

Top safety tips:

• Visit a legitimate thermal spa complex where waters are tested for temperature, minerals and acidity, rather than a natural pool in the wilderness
• Never swim alone
• Always keep your head above water, whether you are in a spa complex or not
• Bring your own bottle of water, stay hydrated
• Exit the water gradually. If you feel faint, tell others and if possible sit or lie down and elevate your legs
• If you are on a walkway, don’t stray from the sign-posted path. Keep an eye on kids and animals.

References

Bassindale T and Hosking M. 2011. Deaths in Rotorua’s geothermal hot pools: hydrogen sulphide poisoning. Forensic Science International. 207(1-3): e28-9. Doi: https://doi.org/10.1016/j.forsciint.2010.11.025

Lord G, Kim N, Ward NI. 2012. Arsenic speciation of geothermal waters in New Zealand. Journal of Environmental Monitoring. 14(12): 3192-3201. Doi: https://doi.org/10.1039/C2EM30486D

Mayo Clinic. 2021. Orthostatic hypotension (postural hypotension). Mayo Clinic. Available from: https://www.mayoclinic.org/diseases-conditions/orthostatic-hypotension/symptoms-causes/syc-20352548 (accessed 21 January 2021).

Olley S. 2020. Reporoa man suffers second-degree burns from Hot and Cold geothermal pools. Rotorua Post. Available from: https://www.nzherald.co.nz/rotorua-daily-post/news/reporoa-man-suffers-second-degree-burns-from-hot-and-cold-geothermal-pools/D2QAMJWU47U2XAWIEJQYU35FNQ/ (accessed 21 January 2021).