Tap water with chlorine may have cancer link

A study from Johns Hopkins raises newfound concerns about the most common water treatment found in American tap water.

Researchers identified new toxic and carcinogenic byproducts that are produced when chlorine is added to regular drinking water. Their findings were published in the peer-reviewed journal Environmental Sciences & Technology.

The Centers for Disease Control and Prevention suggests 4 milligrams of chlorine per liter of drinking water as a safe level.

Carsten Prasse, an assistant professor of environmental health and engineering at Johns Hopkins and lead author of the study, wants to be clear that chlorination itself is not detrimental to human health.

Chlorine frequently is used because it’s effective, affordable and easy to administer, said Ngai Yin Yip, an assistant professor of earth and environmental engineering at Columbia University.

Adding chlorine to drinking water, according to the CDC, kills germs and bacteria and significantly reduces water-borne diseases.

The study finds that compounds that aren’t detected may be detrimental to long-term health.

That includes two forms of the toxic compound and known carcinogen BDA, which haven’t been discovered in drinking water until this study.

Prasse’s team deployed a method that isn’t typically used in water testing, adding an amino acid akin to lysine to chlorinated water. They then inspected the samples for free radicals.