New Study Suggests Cancer-causing Chemicals in Drinking Water Comes from Shampoo, Detergent

water contamination carcinogen NDMA dish detergent photo

Dishwashing detergent is among the household cleaning products containing ingredients that could form a cancer-causing contaminant in treated wastewater. Photo by rubberglovelover via Flickr.
Guest bloggers Andrea Donsky and Randy Boyer are co-founders of

Ingredients commonly found in shampoo, detergents and fabric softener may be the precursor of a suspected cancer-causing chemical in treated wastewater.

In a study published in Environmental Science & Technology, researchers reported that harmful nitrosamines form from quaternary amines, which are found in many consumer products, and since pretreatment with ozone or chlorine does not reduce the amount of nitrosamines that form, many of these nitrosamines end up in drinking water, wastewater and recreational water.One nitrosamine, N-nitrosodimethylamine (NDMA), is of particular interest because it is a toxic organic chemical and a suspected human carcinogen.

Preliminary Findings Yield Grab-Bag of Results
The report is clear that the findings are preliminary. Only a fraction of the hundreds of potential products were analyzed, and, as the report states, there was wide variation in the tendency to act as a precursor to NDMA:

Our calculations are highly preliminary. Consumer products exhibited a range of tendencies to serve as precursors during chloramination, and it is unlikely that any one compound would account for the majority of nitrosamine formation. Certain products, including the Cheer laundry detergent and Pantene shampoo, did not form nitrosamines. However, the NDMA mass yield from Dawn dishwashing detergent was 26 times greater than that for Suave shampoo.

While more research is clearly needed, experiments suggest NDMA and other nitrosamines may form from degradation of quaternary amines by amidogen or chloramino radicals formed from chloramines, which are used to treat water. In other words, the chloramines we're using to treat the water may be helping to produce NDMA.

The good news is quaternary amines may be removed by sedimentation, but as the research points out, "high loadings" from consumer products could mean not all of the quaternary amines are removed, which could mean continued NDMA formation. As a result, researchers suggest evaluating products on a case-by-case basis to determine which produce the highest levels of quaternary amines, with the hope of modifying the formula to reduce the amount of quaternary amines produced.

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