Know Your Environment. Protect Your Health.

N-Nitrosodimethylamine (NDMA)

Tesoro Viejo Master Mwc, Inc.

N-Nitrosodimethylamine is one of the DNA-damaging, cancer-causing contaminants called N-nitrosamines that can form during water treatment with the use of certain disinfectants, such as chloramine. Read More.

Pollution of water sources with effluent from municipal wastewater treatment plants and runoff from animal feeding operations contributes to nitrosamine formation. Fifteen different nitrosamines are listed as carcinogens in the U.S. Department of Health and Human Services National Toxicology Program Report on Carcinogens. The federal government has not set a legal limit for nitrosamines in drinking water and water utilities typically do not test for these contaminants. California has set a public health goal for one of the most common nitrosamines, N-nitrosodimethylamine or NDMA, at 0.003 parts per billion in drinking water, a concentration that corresponds to an estimated one-in-one-million cancer risk.

Click here to read more about disinfection byproducts.

 

20

Samples

0

Samples exceeding legal limit (MCL)

14

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
201836.3 ppt32ND - 77.0 ppt
201922.2 ppt117ND - 46.0 ppt
202015.0 ppt2212.0 ppt - 18.0 ppt
20218.07 ppt337.20 ppt - 9.80 ppt
20222.30 ppt112.30 ppt
2023N/A00N/A

ppt = parts per trillion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 3 ppt

The EWG Health Guideline of 3 ppt for n-nitrosodimethylamine was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

ppt = parts per trillion

All test results

Date Lab ID Result
2018-08-31CA2010017_002_002-201808310845ND
2018-10-16CA2010017_DST_900-20181016090077.0 ppt
2018-11-07CA2010017_DST_900-20181107091532.0 ppt
2019-04-03CA2010017_DST_900-20190403101041.0 ppt
2019-07-10CA2010017_DST_900-20190710093039.0 ppt
2019-09-04CA2010017_002_002-201909041040ND
2019-09-04CA2010017_003_003-201909041055ND
2019-09-04CA2010017_DST_900-20190904095046.0 ppt
2019-09-11CA2010017_DST_900-20190911071528.0 ppt
2019-09-18CA2010017_002_002-201909181020ND
2019-09-18CA2010017_003_003-201909181040ND
2019-09-18CA2010017_DST_900-20190918090539.0 ppt
2019-09-25CA2010017_DST_900-20190925092524.0 ppt
2019-10-02CA2010017_DST_900-20191002083527.0 ppt
2020-01-22CA2010017_DST_900-20200122085518.0 ppt
2020-10-14CA2010017_DST_900-20201014083512.0 ppt
2021-04-14CA2010017_DST_900-2021041408257.20 ppt
2021-07-14CA2010017_DST_900-2021071410109.80 ppt
2021-10-13CA2010017_DST_900-2021101309357.20 ppt
2022-01-12CA2010017_DST_900-2022011208502.30 ppt