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EWG's Tap Water Database — 2019 UPDATE

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Atrazine

Washington Aqueduct Division

Atrazine is a herbicide commonly detected in drinking water that comes from cornfield and other agricultural runoff. It is a hormone disrupter that harms the male and female reproductive systems of people and wildlife. Read More.

Federal laws allow up to 3 parts per billion of atrazine in treated tap water. Water suppliers average atrazine measurements collected over a year, which means that the reported values underestimate intense spikes of elevated exposures during the periods in late spring and early summer when atrazine is applied in large amounts on farm fields.

Human epidemiological studies suggest that federal standards for atrazine are insufficient to protect public health. In 1999 the California Office of Environmental Health Hazard Assessment set a public health goal of 0.15 parts per billion for atrazine in drinking water, based on a study finding increased rates of breast cancer in rats exposed to the chemical. California’s legal maximum for atrazine in tap water is 1 ppb.

Click here to read more about atrazine.

 

50

Samples

0

Samples exceeding legal limit (MCL)

2

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.0238 ppb82ND - 0.1000 ppb
20130.0163 ppb82ND - 0.0700 ppb
20140.0250 ppb82ND - 0.1000 ppb
20150.0250 ppb82ND - 0.1000 ppb
20160.0363 ppb82ND - 0.200 ppb
20170.0290 ppb102ND - 0.200 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.1 ppb

The EWG Health Guideline of 0.1 ppb for atrazine was defined by EWG based on epidemiological studies of human exposure to atrazine in drinking water.. This health guideline protects against harm to the developing fetus, harm to the reproductive system and hormone disruption.

EPA Maximum Contaminant
Level (MCL) 3 ppb

The legal limit for atrazine, established in 1991, was based on a toxicity study in laboratory animals conducted in the 1980s. This limit does not fully protect against harm to the reproductive system, harm to the developing fetus, and hormone disruption.

ppb = parts per billion

All test results

Date Lab ID Result
2012-01-01McMillanND
2012-01-01DalecarliaND
2012-04-01DalecarliaND
2012-04-01McMillanND
2012-07-01Dalecarlia0.0900 ppb
2012-07-01McMillan0.1000 ppb
2012-10-01DalecarliaND
2012-10-01McMillanND
2013-01-01DalecarliaND
2013-01-01McMillanND
2013-04-01DalecarliaND
2013-04-01McMillanND
2013-07-01McMillan0.0700 ppb
2013-07-01Dalecarlia0.0600 ppb
2013-10-01DalecarliaND
2013-10-01McMillanND
2014-01-01DalecarliaND
2014-01-01McMillanND
2014-04-01DalecarliaND
2014-04-01McMillanND
2014-07-01Dalecarlia0.1000 ppb
2014-07-01McMillan0.1000 ppb
2014-10-01DalecarliaND
2014-10-01McMillanND
2015-01-01DalecarliaND
2015-01-01McMillanND
2015-04-01DalecarliaND
2015-04-01McMillanND
2015-07-01Dalecarlia0.1000 ppb
2015-07-01McMillan0.1000 ppb
2015-10-01McMillanND
2015-10-01DalecarliaND
2016-01-01DalecarliaND
2016-01-01McMillanND
2016-04-01DalecarliaND
2016-04-01McMillanND
2016-07-01Dalecarlia0.0900 ppb
2016-07-01McMillan0.200 ppb
2016-10-01McMillanND
2016-10-01DalecarliaND
2017-01-01DalecarliaND
2017-01-01McMillanND
2017-04-01DalecarliaND
2017-04-01McMillanND
2017-07-01Dalecarlia0.0900 ppb
2017-07-01McMillan0.200 ppb
2017-10-01DalecarliaND
2017-10-01McMillanND
2017-12-01DalecarliaND
2017-12-01McMillanND