A new global study suggests that common practices of chlorinating drinking water could raise the risk of some cancers. The study found a 33% higher chance of bladder cancer and a 15% higher risk of colorectal cancer in people exposed to chlorinated water.
Why Chlorine Is Used in Water
Chlorine is used in water treatment because it is cheap, effective, and easy to get. It helps kill harmful germs and prevent waterborne diseases. When chlorine was introduced to water supplies in the 1900s, it reduced deadly diseases like cholera and typhoid fever. This increased life expectancy in many countries.
But over time, scientists began to worry about the risks of chlorination. Since the 1970s, studies have looked into how chlorine interacts with natural materials in water. This interaction can create byproducts that may be harmful to health.
The Risks of Chlorine Byproducts
When chlorine mixes with organic matter, like plant decay, it forms chemicals called trihalomethanes (THMs). Some common THMs are chloroform, bromoform, bromodichloromethane, and chlorodibromomethane. These chemicals can damage DNA and have been linked to cancer in animals.
Recent studies show that even low levels of THMs in drinking water may be dangerous. Many people in the U.S. and Europe drink water with detectable THM levels.
Are the Limits Safe?
In the U.S., nearly 300 million people drink water with THMs. The U.S. Environmental Protection Agency (EPA) allows up to 80 parts per billion (ppb) of THMs in drinking water. The European Union sets a higher limit of 100ppb.
However, this new research suggests that the safe level of THMs could be much lower. The study indicates that the cancer risks may start at just 40ppb of THMs. New York City’s water supply already has levels in this range.
The EPA’s guidelines of 40-60ppb may still be risky. Experts suggest that the safe level of THMs may be closer to 0.15ppb, according to the Environmental Working Group (EWG), a health-focused non-profit group.
How the Study Was Done
This study looked at data from over 90,000 people in 30 different studies. It is one of the largest reviews of this issue. The study found that men are more at risk of cancer from THMs than women. The researchers focused on bladder and colorectal cancers because those are the cancers most linked to THM exposure.
However, scientists still don’t know exactly why THMs mainly affect the bladder and large intestine. They think it may have to do with how the body processes these chemicals.
The Challenge for Water Regulators
This new information puts pressure on water regulators. They must balance water safety with cancer risks. Water from lakes and rivers has more organic matter than water from underground sources. This makes surface water more likely to form THMs.
Reducing chlorine levels too much could make water unsafe. It may not kill germs and bacteria. Still, researchers are looking for ways to reduce the risk of THMs while keeping water safe.
Alternative Methods of Water Treatment
Some other methods of water treatment could help reduce THMs. One option is ultraviolet (UV) light. UV light can kill germs without creating harmful byproducts. Advanced filtration systems could also help. However, these methods are often more expensive and harder to use on a large scale.
Despite these challenges, researchers believe that finding safer water treatment methods is essential.
What Can People Do to Reduce Risks?
The study says that tap water is still safe to drink. However, for those who are worried about THMs, there are ways to reduce exposure. One of the most effective methods is using a water filter with activated carbon. These filters can help remove THMs from drinking water.
Conclusion: The Need for Further Action
Chlorination has been a crucial tool in protecting public health. It has helped prevent deadly waterborne diseases for over a century. But as research shows the cancer risks of THMs, it is clear that action is needed.
Governments and water treatment facilities must find safer ways to disinfect water. This could include reducing THMs in drinking water or using alternative treatments. More research is needed to protect public health and reduce long-term risks.
For more information, visit New York Mirror.
