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  • Writer's pictureGary Moller

Is the Waikato River a public health hazard due to arsenic contamination?

Updated: Feb 15

It has long been known that the Waikato River has elevated levels of arsenic from thermal water feeding into it from natural sources, as well as via discharge from geothermal power stations. There is no debate about there being elevated levels; the only question for that remains unanswered is how harmful are these levels of arsenic to human health?

Lake Maraetai: a focal point for arsenic contamination

Lake Maraetai, on the Waikato River, receives the outfall waste from the Kinleith paper mill and has done so for decades. According to research, this lake may be the most toxic portion of the Waikato River with regards to levels of arsenic in the lake bed sediment.

Our own independent testing of Lake Maraetai Water shows that the lake water has levels of arsenic that are well in excess of drinking water standards for this toxin.

The official limit for drinking water is 0.001 grams of arsenic per cubic meter of water. Levels measured by Eurofins EFS on 19 December, 2016 found 0.026 grams of arsenic per cubic meter of water from Lake Maraetai!

This elevated contamination by arsenic may be due, in part, to the historic discharge of arsenic from Kinleith and nearby timber mills, causing a buildup of this and other toxins in the lake's sediment. What may also be contributing to unusually high levels of arsenic in Lake Maraetai is the floxing effect on heavy metals by high levels of tannin and iron contained in the mill discharge. Iron and tannin bind with heavy metals, such as arsenic, making them insoluble, thus depositing the toxins in lake sediment, instead of continuing to flow downstream.

Lake Maraetai, with the village of Mangakino nestled on its shores, is now a popular holiday venue. Are children and adults at risk of arsenic contamination and developing any of the long list of health problems associated with heavy metal buildup? Are they at risk by playing in the water and stirring up the sediment, eating watercress and trout, and from using aquatic plants as compost on their vegetable gardens.

The answer is "YES!" More about this later, along with the evidence.

Are we slowly and quietly poisoning the citizens of our largest city?

15% of Auckland City's water is taken from the Waikato and this may rise to as high as 30% during times of drought. We are not aware of any processing during the "treatment" of this water to remove heavy metals, including arsenic which is present in the Waikato River.

Waikato water intake for Auckland

Elevated arsenic has been found in the bodies of a family after bathing in Lake Maraetai

Elevated tissue arsenic has been identified in a family of two adults and two children who bathed in Lake Maraetai, adjacent to the Kinleith outfall. The family has a holiday home in Mangakino. Despite being a very health-conscious family they all had subtle health problems that were consistent with arsenic toxicity, principally varying degrees of unusual fatigue.

The image below shows the point of discharge of Kinleith waste water into Lake Maraetai. Mangakino is on the other side of the lake, about 800 meters away from the discharge point.

Arrow showing point of discharge of Kinleith waste water into Lake Maraetai

Hair Tissue Mineral Analysis: the Gold Standard for assessing historic exposure to toxic elements

If exposure to a toxin is suspected, this will usually show on the InterClinical Laboratories Hair Tissue Mineral Analysis (HTMA). The levels present may be low, but this may be due to depressed metabolic processes, resulting in poor elimination of toxins, sequestering of the toxin, or most of it having been eliminated from the body prior to the hair sample having grown.

Rather than have the toxin in circulation where it can cause enormous harm, the body will quickly sequester what it can not excrete. Toxins are sequestered in tissues such as the bone and fat, and in organs like the liver, where it remains until the body is able to safely mobilise and excrete some of the toxin. This sequestration can be for years and these toxins gradually break the person's health. I liken the effect of these toxins as being like rust in your car's chassis. It's there but you don't know until things start falling to bits and that is far too late!

Hair, skin and nails are one of the body's detoxification pathways, hence any elimination of a toxin may be recorded for posterity in the hair that was growing at the time of elimination.

It is from the use of hair tissue analysis that it was concluded, a hundred years later, that Napoleon Bonaparte was quietly and slowly poisoned with arsenic, as was the legendary race horse, Phar Lap, killed with a huge single dose of arsenic. This lethal dose of arsenic is recorded in Phar Lap's hair which kept growing for several hours after death, hence the record.


A family with consistent evidence of exposure to arsenic, presumably from Lake Maraetai

The father:

Father's HTMA showing presence of arsenic associated with Lake Maraetai

Despite having the highest levels of arsenic on the HTMA, the father is, arguably, the least affected of the family, in terms of presentation of symptoms. He may have had the highest exposure. That may be the case, but there is another explanation.

High levels of arsenic on the HTMA may be due to his overall healthier state, including "Fast One" metabolic typing, which means he may be in a better position than the rest of the family to eliminate arsenic as it enters the body. Hence the elevation of arsenic in the hair.

The mother:

Mother's HTMA showing presence of arsenic associated with Lake Maraetai

While there is a hint of arsenic, the mother has the worst of symptoms, including overwhelming fatigue. Her profile is one of metabolic exhaustion, including "Fast 4" which is far from ideal (Fast one or Slow One are the ideals). Low levels of arsenic, in her case, may be due to poor elimination or less environmental exposure to the toxin in the first place, or both.

The youngest child:

Again, there is the unusual presence of arsenic (arsenic is usually found in occupations like farming and building where treated timber is used - not children).

Child's HTMA showing presence of arsenic associated with Lake Maraetai

The oldest child:

Arsenic in the hair sample, yet again. Four consistent results.

Child's HTMA showing presence of arsenic associated with Lake Maraetai

Action taken

After determining that the most likely source of contamination has to be Lake Maraetai, the family has made the difficult decision to avoid bathing in the lake, despite their holiday home, which they visit often, being on the lake's shore.

Special nutrients that aid the safe elimination of arsenic were prescribed for the family to take on a daily basis.

Results to date

There has been a noticeable improvement in the health and energy of all the family members, especially the mother who was the most unwell by far. She has benefited most and is looking much better. She was our priority, so this is a most pleasing outcome.

The husband has entered the Coast-to-Coast multisports endurance race from Hokitika to Sumner Beach and is in the final stages of steady training.

We have only repeated the father's HTMA, at this stage, because we needed his follow up test to help tweak his race nutrition. The rest of the family will be retested in the next few months.

Here is the Nutritional Chart from his latest report of December 2016, comparing with his first report of May 2106:

The father's repeat HTMA:

Arsenic has remained elevated, even with several months of carefully avoiding further exposure to the suspected source of contamination (lake Maraetai). He is fitter than ever and in even better health as compared to at the time of his first HTMA and went on to complete the exhausting Coast to Coast race.

Going by what we understand about how the body responds to one or more exposures to a toxic element such as arsenic, we can assume:

  • He has a deposit of arsenic which has been sequestered deep within his body.

  • He is steadily eliminating this toxin and progressively feeling better while doing so.

  • The process of clearing his body of arsenic is far from over and is going to take many more months, if not years.


Recommendations for health officials

Numerous studies show that there is arsenic contamination of the Waikato River. This is beyond dispute.

What is not known and poorly studied to date is:

Does the arsenic in the Waikato River present a hazard to human health?

This report presents credible evidence that:

  • A family has been contaminated by arsenic.

  • Their symptoms of ill health are consistent with exposure to arsenic.

  • The only possible source of contamination that can be identified is bathing in Lake Maraetai.


Health officials must exercise the "precautionary Principle" for health: they must issue a public health hazard warning.

Action: Notify the public that

  • Arsenic is present in the Waikato River.

  • While its effects on health, at these levels of contamination, are presently uncertain, please refrain from bathing in the water, or drinking from the river. This includes the residents of Auckland City.

It is recommended, with urgency, that scientific studies are conducted to determine if there is arsenic uptake by humans from bathing in, and drinking Waikato River water.


Further reading/evidence:

  1. The distribution and fate of arsenic in the Waikato River system, North Island, New Zealand Interestingly, even though the numbers were quite high, somehow they managed to draw the conclusion that the Waikato River is OK source of drinking water for Auckland if they use it in combination with the rain catchment. And maybe not use it during the summer months because the arsenic levels in the water increase above the WHO guidelines. They also say that WHO limit is extremely conservative so they foresee no real problem.

  2. Waikato River Watercare

  3. Waikato River water quality

  4. Elevated concentrations of arsenic (As) in the river mean that untreated river water exceeds the water quality guidelines for drinking-water at all river sites downstream of Aratiatia

  5. Arsenic rests in the sediment of most lakes linked to Waikato River, and in one the arsenic level is on average EIGHT TIMES (being an average, the peak excess levels must be higher) more that the NZ sediment quality guidelines for ecological protection

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