New Cancer Causing Agent from Household Products Found in our Water

In the new study, Yale researchers found evidence that common household items such as cleaners, shampoos and detergents are creating a chemical cocktail. These products are combining with a chlorine compound and resulting in a new cancer causing agent in water supplies that comes from sewage treatment plants. The compound is NDMA, which is a nitrosamine. Nitrosamines are known to be highly carcinogenic and have been especially linked to bladder cancers.

The new study was conducted by researchers at the Yale Department of Chemical Engineering and was published earlier this year in Environmental Science and Technology. Thus far scientists know little about the new nitrosamine compound other than that it causes cancer. Though the scientists are not sure exactly how NDMA forms, they suspect that the combination of compounds found in common household items lead to the formation of NDMA when water is chlorinated.

Researcher William Mitch and colleagues noted that scientists have known that NDMA and other nitrosamines can form in small amounts when wastewater and water are disinfected with chlorine. Although nitrosamines are found in a wide variety of sources, such as processed meats and tobacco smoke, scientists have known little about their precursors in water. Previous studies with cosmetics have found that substances called quaternary amines, which are also ingredients in household cleaning agents, may play a role in the formation of nitrosamines. Quaternary amine monomers are widely used in antibacterial soaps and mouthwashes, while polymers are used in shampoos, detergents, and fabric softeners.

In the study, the researchers collected treated waste water from waste water treatment facilities in three Connecticut cities. The researchers also examined the effects of adding common household cleansers, shampoos and detergents.

Their laboratory research showed that when mixed with chloramine, household cleaning products including shampoo, dishwashing detergent and laundry detergent formed NDMA. The researchers' report noted that sewage treatment plants may remove some of the quaternary amines that form NDMA. However, quaternary amines are used in such large quantities it is believed that some still persist and have a potentially harmful effect in the water treated at sewage treatment plants.

Notably, the same group of researchers previously found high levels of nitrosamine disinfection byproducts in swimming pools, hot tubs and aquariums that had been disinfected with chlorine. The highest nitrosamine detected in chlorinated swimming pools and hot tubs reached levels up to 500-fold greater than the drinking water concentration of nitrosamines associated with a one in one million lifetime cancer risk.