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  • Gary Moller

Is bathing in Central North Island thermal water endangering your health?

(updated April 2022)


Arsenic is the most common toxin seen in hair tissue analysis in New Zealand. Treated timber and geothermal water are the two most common sources of arsenic, with the third being contaminated bore water. These appear to be taboo topics for discussion, probably due to thermal pool tourism, and our reliance on softwoods as building materials. Some regions such as Central Otago rely on bore water. If arsenic is in the rock strata this may contaminate the water supply.

Softwoods usually require treatment with chemicals, including arsenic to prevent rotting and infestation by insects. Unlike manual saws, chisels and planes, modern high-powered woodworking machinery creates fine dust and the heat vaporises chemicals, including arsenic. So, despite modern health and safety practices, the problem is getting worse rather than better.

Bathing in geothermal waters is a popular past-time with many health claims. Some waters, particularly the central North Island have extremely high levels of arsenic.

Working with arsenic-treated timber or bathing in some geothermal pools exposes the person to the risk of arsenic contamination: This is a fact!

The questions to be answered are these:

  1. How many people in New Zealand have toxic levels of arsenic in their bodies?

  2. What are the consequences to their health?

  3. Assuming there is a public health problem here; what, if anything, is being done about it?

The evidence leads me to conclude that countless thousands of people have had their health compromised by exposure to arsenic. I have now had so many cases of arsenic-related ill health that it runs into the hundreds, perhaps more than one thousand: I have lost count.

This article is about the hazards of bating in geothermal water which contains toxic levels of arsenic.


Is bathing in Central North Island thermal water endangering your health?

In a word, the answer is "Yes!", if you bathe in the wrong waters. There are thermal pools in the Central North Island that are so toxic with arsenic that they should be shut down, or at least, come with health risk warnings. The highest levels of arsenic-contaminated thermal waters tend to concentrate in the Tokaanu region, bordering Lake Taupo. This may represent a hazard to health.

I asked this question myself, when my partner, Alofa fell unusually ill after bathing in private mineral pools in Tokaanu. It gradually dawned on us that she had been affected by a poison, which was later identified as arsenic. While she was successfully treated, the process of learning more about the source of contamination, then confirming it with laboratory tests of the suspect water and identifying other cases of ill health coinciding with bathing in the same water has taken a while. I am now confident of the evidence to put it out for public attention and scrutiny. Hence this report.

How arsenic gets into geothermal water

I am not an expert in geothermal geology; but here is my understanding of what is going on:

High levels of arsenic in thermal water happen when super-heated subterranean geothermal water passes through arsenic-laced rock while on its way to the surface, dissolving the mineral as it goes. One geothermal spring may be high in arsenic and/or other minerals; whereas another adjacent to it may have a different composition: it all depends on what kind of rock the water passes through.

Some, if not all geothermal springs in Tokaanu, pass through arsenic-laced rock, producing some extremely high readings of arsenic in the water.

Is Tokaanu a toxic thermal wonderland?

The answer is "Yes!"


"Total arsenic and four arsenic species; arsenite (iAsIII), arsenate (iAsV), dimethylarsinic acid(DMAV) and monomethylarsonic acid (MAV), are reported in 28 geothermal features from the Taupo Volcanic Zone (TVZ) and Waikato region of New Zealand. Samples were collected for arsenic speciation analysis via a solid phase extraction (SPE) kit allowing the separation, stabilisation and pre-concentration of the species at the time of sample collection in the field.

This is the first research to present data for arsenic species collected by this technique in geothermal waters from New Zealand. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), ranged from 0.008 to 9.08 mg l−1 As. The highest levels were discovered in three features in Tokaanu (Taumatapuhipuhi, Takarea #5 and #6), with arsenic concentrations of 8.59, 8.70 and 9.08 mg l−1 As, respectively. Inorganic arsenic species were predominant in the geothermal waters, with arsenite contributing to more than 70% of the total arsenic in the majority of samples. Organic species were also determined in all samples, indicating the presence of microbial activity.

A potential risk to human health was highlighted due to the high levels of arsenic, mainly as arsenite, in geothermal features linked to bathing pools. Further research is needed into dermal absorption as a potential route of arsenic exposure whilst bathing in these hot pools, as it may contribute to an occurrence of acute arsenic-related health problems."

Arsenic speciation of geothermal waters in New Zealand Gillian Lord, Nick Kimb and Neil I. Ward J. Environ. Monit., 2012,14, 3192-3201 DOI: 10.1039/C2EM30486D First published online 12 Nov 2012!divAbstract


I have corresponded with one of the authors of this study, Neil Lord, who has been very helpful. There is no question that arsenic levels are extremely high in some or all geothermal waters in Tokaanu. The one question coming from his research, that is yet to be answered, is how much of this toxin is absorbed into the body of a person while bathing in these waters? I find it astonishing that public health officials have not made it a priority to answer whether people are being contaminated with arsenic and their health damaged.

Years have passed with little apparent action and one must wonder just how many people have been harmed in the meantime.

New Zealand markets itself to the rest of the world as being a clean and green paradise, including where one can bathe in health-enhancing geothermal hot pools.

Is this one Big - Fat lie?

This article presents compelling evidence that there is a relationship between bathing in arsenic-contaminated waters and elevated levels of body tissue arsenic after the bathing - as well as the subjects then falling ill with ailments that are consistent with arsenic toxicity.

In addition, I supply evidence below of tissue analyses showing low levels of arsenic prior to the bathing and I can show tissue levels returning to low after avoiding further exposure and after giving nutrients that help chelate arsenic out of the body.

The most compelling evidence is all of these people reported feeling ill shortly after bathing in these waters, sufficient to seek medical assistance.

What is arsenic and what is arsenic toxicity?

Arsenic is an element of the Universe that is classed as a "metalloid". Arsenic is toxic to human health when in concentrations of more than a few parts per million. Enzyme activity within cells is what drives metabolism (life). Arsenic displaces desirable elements within enzymes, such as selenium, zinc and sulphur, causing the enzyme to either slow down or stop completely. It also interferes with anti-oxidants such as beta carotenoids.

In this article, we are discussing arsenic "toxicity" not "poisoning". Toxicity refers to low levels of exposure to a toxin that may lead to chronic and often subtle symptoms of ill health that gradually weaken and wear a person down as the months turn into years. "Toxicity" levels of exposure and their health consequences are usually ignored or dismissed by health experts as being insufficient to cause illness. This is, of course, disputed.

Symptoms of arsenic toxicity

Symptoms of arsenic toxicity centre around chronic fatigue, aching muscles, aching joints, sore tendons, rapid onset of arthritis, various connective tissues disorders, including frozen shoulder and tendon contractures, thyroid issues, poor hair, skin and nails, brain fog, viral infections and a long list of immune-related disorders, such as rheumatoid arthritis, psoriatic arthritis and psoriasis.

Arsenic is a carcinogen, possibly because of its interference with zinc and selenium.

Arsenic - the quiet poison

Arsenic was once the poison of choice by disaffected wives, as a means of quietly knocking off the man she had come to hate. Arsenic was fed to Napoleon Bonaparte and was the most likely cause of his death. The legendary NZ racehorse, Phar Lap, was nobbled by a massive dose of arsenic, possibly added to his oats. Not nice!

Hair Tissue Mineral Analysis (HTMA) were used to confirm the presence of arsenic in toxic amounts in both Phar Lap and Napoleon Bonaparte at their times of death. The same test, using mass spectrometry, is what is employed here as evidence of arsenic toxicity from bathing in geothermal waters.

The fascinating origins of "Drop-Dead Gorgeous" and "Green with envy"

Arsenic was used during Victorian times as a medicine for the treatment of diseases, such as cancer and syphilis. I guess, in these cases, the diseases were worse than the treatment!

What is not so well known is that arsenic-soaked fabrics were popular for their brilliant green sheen. Arsenic was also popular for blemish-free skin.

Arsenic - the secret to a good complexion

"Beauty Soap". Popular during Victorian times, probably producing a slightly green complexion.

Skeleton dressed in an arsenic laced Victorian Gown

A stunning Victorian woman attired in a gown that was the envy of the day.

Arsenic laced Victorian Gown

A drop-dead gorgeous gown from Victorian times.

Images source: The Pragmatic Costumer

Blood tests for assessing arsenic contamination

Blood tests are most helpful because the test can tell if exposure to arsenic has been very recent, or if a therapy, like chelation, has been successful in mobilising a deposit that is hidden deep within the body.

Blood tests can be misleading if the exposure to the toxin has been longer than a few weeks ago. This is because toxins like arsenic will not remain in the circulation for longer than a few days before dropping steeply in blood concentration. The body will do all it can to get this poison out of circulation as quickly as it can so as to minimise the damage. It does this by excreting the toxin via the bile, urine, sweat and shedding hair, skin and nail tissue. What can not be immediately excreted via these pathways is sequestered in "safe" or relatively inert tissues, such as the bones and fat, and also in organs like the liver. As the body is able, these sequestered deposits will be gently excreted in fits and starts over time, often years, if not decades. Its a slow process if not assisted by chelation therapies.

The Hair Tissue Mineral Analysis (HTMA) for assessing arsenic contamination

Any episodes of the ingestion of a toxin such as arsenic and any later episodes of detoxification can be identified by way of the HTMA - so long as the hair sample is of hair that was growing at the time of the exposure and/or detoxification. As with Phar Lap and Napoleon Bonaparte, their hair samples remained an accurate forensic record, valid many decades later.

Why do polluters and their insurers tend to favour blood tests over the HTMA?

Polluters and their insurers always seem to favour the blood test over the HTMA for measuring worker or public exposures to toxins. A cynic, which I am, may assume that "polluters" will tend to favour the scientific tests that minimise the downsides of their polluting ways.

A blood test will show only recent exposure - not historical. So long as there is a delay of a week or two after being contaminated the affected population will tend to produce "clean" blood test results. Not so with the HTMA which can pick up the tell-tale traces months and even years later.

As a hypocritical contradiction, the very same agencies that poo-pooh the HTMA for toxic exposures may use the exact same test for detecting and firing employees who may have smoked a joint several months ago. By the way, the HTMA service that I provide never ever will test for illicit substances.

You can learn more about the HTMA by going here:

Tokaanu thermal water is known to be highly toxic with arsenic

Please Note:

This report does not apply to hot pools that use municipal water that is heated by geothermal water by way of a closed heat exchange system. In this report, we are referring to geothermal waters that have come directly from geothermal hot springs.

The image below is the HTMA for my partner, Alofa, who fell ill within days of bathing in a natural thermal hot pool in Tokaanu, in November 2014. Symptoms included extreme fatigue, and muscle and joint pain.