Arsenic in Well Water

Arsenic: The Little-Known Carcinogen in NL Well Water & How to Get Your Water Tested for Free

The Impact of Arsenic-Contaminated Well Water

Written by Dawn Gough, MTM  with contributions from Martin Pothier, PhD.


Arsenic is a colourless, odourless, toxic heavy metal that can sometimes be found in groundwater. Groundwater is a major water source in many rural, small communities. Studies have shown that certain areas on the island portion of Newfoundland and Labrador have elevated levels of arsenic in groundwater, ranging up to 60 mg/L, putting residents who use private wells in those areas at an increased risk of exposure. The maximum acceptable concentration of arsenic in Canadian drinking water is 0.010 mg/L. Long-term exposure to arsenic from drinking water can have devastating effects on human health, including cancer. If you need help with testing your well water, please contact us by calling 709-766-1859.

Sources of Arsenic

Arsenic can enter drinking water through natural or anthropogenic sources. The specific causes of arsenic contamination in NL may vary depending on the location and the history of industrial activities in that area. 

It is known that the province of NL has 2508 contaminated sites, the highest number of contaminated sites per capita in Canada. Government and local communities must continue to monitor and remediate contaminated sites to protect human health, safety, and the environment. We must do a better job regulating industrial activities to prevent further environmental damage.

Some of the most common causes of arsenic contamination in drinking water include:

  1. Natural Occurrence: Arsenic is a naturally-occurring element that can be found in rocks and soils. It can leach into ground and surface water through weathering and erosion.
  2. Mining and Industrial Activities: The mining of certain minerals and industrial processes can release arsenic into the environment, which can then contaminate nearby water sources.
  3. Agricultural Activities: The use of arsenic-containing pesticides and fertilisers can contribute to arsenic contamination in drinking water.
  4. Historical Contamination: Arsenic was used in many industrial and agricultural applications in the past, and could be present in soil and groundwater as a result.
  5. Ageing Infrastructure: Old water supply systems and corroding pipes may lead to the release of arsenic into drinking water.

Health Effects of Exposure to Arsenic

While arsenic can contaminate food, air and water, all major chronic poisonings have stemmed from water and this is usually the predominant exposure route. As a Group 1 Carcinogen, long-term exposure to arsenic is known to increase the risk of lung, skin, bladder, and kidney cancer. The first symptoms of exposure to high levels of arsenic are usually observed in the skin and include pigmentation changes, skin lesions and hard patches on the palms and soles of the feet (hyperkeratosis). 

Even though it seems there is a barrage of carcinogenic toxins in our environment, there are things we can do to reduce our overall toxic burden, including regularly testing private water wells for contamination, and if any toxins are found, using filtration systems and other treatment methods to remove them. Arsenic is not removed by pitcher-type filtration units or boiling.

Taking steps to minimise exposure to chemicals, heavy metals, and toxins can help reduce the risk of cancer and other health problems. Avoiding pesticides and other chemicals, and being mindful of potential industrial pollution in your area will reduce your overall susceptibility. Furthermore, it is imperative to advocate for policies and regulations that prioritise the protection of public health and the environment.

Well Water Testing and Treatment

The government of NL conducts regular testing of public drinking water supplies to ensure they are safe for consumption. However, private wells fall outside of this mandate and it is the responsibility of the well owner to ensure that their water supply is safe. 

There are a significant number of private wells in the province, serving around one-fifth of the population. According to Ecotoxicologist Martin Pothier, PhD, when treating water contaminated with arsenic, there are two steps to consider: 1) oxidize the arsenic, and 2) remove the arsenic.

“There are many oxidizers to choose from, common ones include bleach and peroxide, while less common (and more complicated) ones include UVC lamps and ozone gas. To remove arsenic, you can precipitate it in a tank or use membrane filters like reverse osmosis. Remember that it’s very important to test your water before and after the treatment.” - Ecotoxicologist Martin Pothier, PhD 

What we are Doing 

The EnTec team is very concerned to hear about recent reports of arsenic found in well water on the island of Newfoundland. Our company is taking proactive measures to help residents who may be affected by arsenic contamination. This includes offering free well water sampling and analysis to individuals living in communities with suspected contamination. Water samples will be independently collected and analysed by our Environmental Technologist, and we will share the results with you. Note that this service is only for private wells and not for public drinking water supplies which are regularly tested by government. 

Alternatively, if you are comfortable with testing your own water, you can drop into your local government service centre for a free test kit. 

Final Remarks and Next Steps

In order to protect the health of residents in NL, it is crucial that we continue to study the causes of arsenic contamination and develop effective strategies for addressing it. A long-term sustainable view of industrial projects must be taken, with polluting companies held responsible for site closure, rehabilitation, and any future contamination issues. Additionally, the government may consider expanding their testing mandate to include private wells to ensure the safety of all residents. 

It is necessary for residents to have their well water tested for contaminants before digging, and regularly monitor their water supply to ensure that the water remains safe to drink. Alternative sources of drinking water or treatment systems must be considered if high levels of arsenic are found. Methods such as anion exchange resin, adsorption filters, reverse osmosis, and distillation can effectively remove arsenic from drinking water. 

Arsenic in drinking water is a serious public health concern that can have detrimental health effects. By taking necessary precautions and understanding the risks associated with arsenic exposure, we can help protect ourselves and our communities from the serious health effects of this toxic element.

“EnTec is dedicated to advocating for the protection of human health and access to clean drinking water in our local communities. Our next steps to ensure safe well water here at home is to provide awareness of arsenic contamination in groundwater, education on its impacts and sources, free testing for private well owners, consultation on treatment options, and urging governments and industry to implement policies to limit the release of contaminants into the environment.”


© EnTec Consulting HSE Solutions. 2023.