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EWG's Tap Water Database — 2019 UPDATE

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Atrazine

Three Valleys Municipal Water District

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.

 

28

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012ND60ND
2013ND50ND
2014ND40ND
2015ND20ND
2016ND50ND
2017ND60ND

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
2012-04-173761-002-1100ND
2012-05-153761-002-1100ND
2012-06-133761-004-1200ND
2012-06-133761-002-0945ND
2012-09-119588-004-0800ND
2012-09-119588-002-0000ND
2013-03-053761-002-1040ND
2013-06-113761-002-0830ND
2013-06-253761-004-0930ND
2013-09-173761-002-0000ND
2013-12-173761-002-1000ND
2014-05-133761-004-1000ND
2014-05-133761-002-1034ND
2014-06-103761-004-1030ND
2014-09-163761-004-1101ND
2015-03-103761-002-0930ND
2015-06-093761-004-0940ND
2016-03-153761-002-0900ND
2016-06-213761-004-1006ND
2016-06-213761-002-1030ND
2016-09-133761-002-1000ND
2016-12-133761-002-1020ND
2017-03-213761-004-1040ND
2017-05-163761-004-0900ND
2017-05-163761-002-0800ND
2017-06-213761-004-1100ND
2017-06-213761-002-1000ND
2017-09-123761-002-0900ND