Disinfection of drinking water has been a major public health achievement, protecting against diseases like cholera and typhoid. However, this process also creates harmful contaminants known as disinfection byproducts (DBPs), which form when disinfectants like chlorine react with organic matter such as animal manure or soil particles. These byproducts are linked to serious health risks, including cancer and fetal development issues.
The Dangers of DBPs
Scientists have identified over 600 DBPs in drinking water, some of which are associated with DNA damage, miscarriage, and birth defects. Two of the most common DBPs, total trihalomethanes (TTHMs) and haloacetic acids (HAA5), are known to increase the risk of bladder and colorectal cancer. Exposure occurs through drinking tap water, preparing food with it, and even bathing or swimming.
Although some utilities have switched to alternative disinfectants like chloramine or ozone to reduce TTHMs and HAA5, these substitutes may create other harmful byproducts. A 2024 study identified a previously unknown byproduct, chloronitramide anion, in systems serving over 100 million Americans, raising new concerns about the safety of treated water.
How to Reduce DBPs in Water
Preventing DBPs starts with keeping pollutants out of water sources. Measures like creating buffer zones near rivers and reducing agricultural runoff can limit contamination. Water treatment plants can also use carbon filtration and maintain pH levels to reduce DBP formation.
For individuals, using a carbon filter at home is an effective way to lower exposure, especially for vulnerable groups like pregnant individuals. Checking your water quality through resources like EWG’s Tap Water Database can help determine the best filtration method. Strengthening federal and state regulations on DBPs is also essential for long-term protection.
