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What are the Cancer-Causing Contaminants in Water?

by Peter Lombardi

Quality Specialist, Consultant

> 2 min read

What are the Cancer-Causing Contaminants in Water

Common cancer causes include a poor diet, lack of exercise, smoking cigarettes, too much sun exposure, or an inherited genetic predisposition. 

However, one of the lesser-known potential causes is the tap water in your household. Some municipal water supplies contain harmful contaminants that over time can increase your risk of developing lung, bladder, skin, or bowel cancer. 

It’s crucial that you’re aware of any carcinogens that may be present in your household supply, so you can take necessary measures to improve the quality of your domestic water system and protect your family from serious health problems.


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The National Problem With Cancer-Causing Contaminants in Drinking Water 

In 2019, a groundbreaking study showed that various carcinogens in drinking water were the cause of over 100,000-lifetime cancer cases in the United States. Although the EPA introduced the Safe Drinking Water Act nearly 50 years ago, reports estimate that, throughout the United States, around 20% of privately run water systems contain unsafe levels of contaminants. 

These contaminants include natural chemical elements like arsenic and radon, along with nitrates produced by man-made fertilizers. If you ingest drinking water that contains high levels of these types of carcinogens, you increase your risk of developing cancer and suffering severe chronic illnesses.

The Main Cancer-Causing Contaminants in Water 

Recent studies found more than 20 carcinogens in the drinking water across all 50 states, including benzene, vinyl chloride, and bromate. However, there are six major and common contaminants that you should look out for in your household supply. 


In 2017, researchers cited that around 2.1 million people in the USA use water with high traces of arsenic. 

When it’s in its primary inorganic form, arsenic is a toxic and destructive chemical element. This element exists in bedrock on the earth’s outer crust, and it often dissolves into groundwater supplies throughout the United States. 

Many commercial companies also use arsenic to manufacture useful alloys like copper and lead, so the surface run-off of industrial pollution can also contaminate vital sources of drinking water. 

Arsenic is a carcinogen that can damage your body in several ways. If you consume excessively high levels of this inorganic chemical, you may develop bladder, lung, and skin cancer as a result. You might also experience pulmonary disease and significant cardiovascular issues. 

Short-term symptoms of arsenic ingestion include vomiting, gastrointestinal problems, muscle stiffness, and cramping. If you experience acute arsenic poisoning, there is an imminent risk of death, and you should seek immediate medical attention. 

Volatile organic compounds and nitrates 

Volatile organic compounds (VOCs) are often used for commercial or industrial manufacturing, whether as components of products like nail polish and paint or as solvents in pesticides. Unfortunately, these chemicals usually vaporize into the air and infuse with the groundwater supply. 

When you consume water that contains traces of VOCs, you might experience nausea, chronic kidney issues, liver damage, and cancer. Short-term effects include respiratory issues, loss of coordination, feeling faint, and blurred vision.

If you are exposed to an acute level of VOCs in your water supply, you may experience a nervous system shut-down, where your body’s psychomotor functions stop working. 

Many agricultural fertilizers contain nitrate, and when farmers spray this synthetic substance on their crops, the nitrate can seep down through the soil and into groundwater and wells. When you consume nitrate, the body converts this chemical into nitrite, which in turn reacts with carboxamides and amines in your digestive tract to create carcinogenic N-nitroso compounds (NOCs). 

Perfluoroalkyl substances 

Polyfluoroalkyl substances (PFAs) are water and oil repellent chemicals that you’ll find in non-stick pans, finishes, paints, waterproof clothing, and various common household cleaning products. 

If you ingest water that contains high levels of PFAs, you may experience a rise in cholesterol and various issues with your immune system. More specifically, long-chain PFAs labeled as perfluorooctanoic acid (PFOA) are potential carcinogens. Consuming this chemical may increase your chances of developing kidney and testicular cancer. 

Disinfection byproducts and chlorine

Many domestic water supplies are treated with chlorine. This element acts as an oxidizing agent that removes unpleasant odors and bacteria from the water. However, chlorine often reacts with various compounds within the water supply, creating disinfection byproducts like haloacetic acids, bromate, and trihalomethanes (THMs). 

Many of these disinfection byproducts (DBPs) can have major adverse effects on your physical wellbeing. Research shows that long-term DBP exposure can lead to the development of bladder cancer. In 2014, BMC Cancer published an article that found a link between colon cancer and bromoform, a THM type. 


Radionuclides like radium, uranium, and radon come from natural and industrial sources and sometimes get into groundwater supplies. When you consume water with high levels of these chemical elements, you are at an increased risk of developing cancer. That’s because these elements break down and decay when they’re inside your body, releasing harmful alpha, beta, and gamma radiation. Radiation exposure works to disrupt your body’s cellular processes, which leads to uncontrolled and excessive cell growth or cancer.

This radiation can also lead to acute sickness, cardiovascular troubles, and severe kidney problems. 


Like many potentially destructive radionuclides, this chemical comes from the natural environment and various industrial sites. Chromium-6 is a certified carcinogen, and at high levels, is linked with lung cancer. 

Other symptoms of chromium-6 ingestion include serious respiratory issues, pneumonia, pulmonary problems, and bronchitis. You may also suffer from a punctured, perforated, or ulcerated septum. 

Recent studies show that over 200 million Americans have used water contaminated with chromium-6, so this chemical is a major source of concern in the United States.

"If you are exposed to an acute level of VOCs in your water supply, you may experience a nervous system shut-down, where your body’s psychomotor functions stop working. " 

The Bottom Line

It’s natural to feel concerned when reading through this information about destructive and harmful contaminants in groundwater and well supplies, but fortunately, there are many ways you can improve the quality of your domestic supply. 

Consider investing in a premium-quality water filter that removes chlorine, arsenic, and VOCs from your household water. You can also invest in a reverse osmosis filtration system and install an under-sink unit for the most effective results.

Peter Lombardi

About the Author

Peter is a Los Angeles based water quality specialist, and works as a surveyor for businesses and communities looking to be informed and active about the quality of their water. He shares his expertise with 64 oz. to ensure everything is accurate, and to prevent the spread of misinformation about water contaminants.