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EWG's Tap Water Database — 2019 UPDATE

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Atrazine

St. Louis City

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)

22

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.594 ppb107ND - 1.56 ppb
20130.295 ppb63ND - 0.660 ppb
20140.143 ppb82ND - 0.580 ppb
20150.150 ppb82ND - 0.660 ppb
20160.0810 ppb102ND - 0.470 ppb
20170.460 ppb86ND - 0.930 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
2012-02-16CRCW021612M508ND
2012-02-17HBCB021712M508ND
2012-05-09AB717960.540 ppb
2012-05-09AB71797ND
2012-05-09HBCB050912M5081.21 ppb
2012-05-21CRCW052112M5081.56 ppb
2012-09-25HBCB092512M5080.680 ppb
2012-09-25CRCW092512M5081.03 ppb
2012-11-07CRCW110712M5080.540 ppb
2012-11-07HBCB110712M5080.380 ppb
2013-03-21CRCW032113M508ND
2013-03-21HBCB032113M5080.560 ppb
2013-05-06AB97904ND
2013-05-06AB979030.660 ppb
2013-09-20CRCW092013M5080.550 ppb
2013-09-20HBCB092013M508ND
2014-03-27CRCW032714M508ND
2014-03-27HBCB032714M508ND
2014-06-02AC237390.560 ppb
2014-06-02AC237380.580 ppb
2014-10-24HBCB102414M508ND
2014-10-29CRCW102914M508ND
2014-12-15HBCB121514M508ND
2014-12-16CRCW121614M508ND
2015-03-17AC44660ND
2015-03-17AC44661ND
2015-06-01AC471060.540 ppb
2015-06-01AC471070.660 ppb
2015-09-30HBCB093015M508ND
2015-09-30CRCW093015M508ND
2015-12-11HBCB121115M508ND
2015-12-23CRCW122315M508ND
2016-03-31HBCB033116M508ND
2016-03-31CRCW033116M508ND
2016-05-17HBCB051716M508ND
2016-05-23CRCW052316M508ND
2016-06-06AC758640.470 ppb
2016-06-06AC758650.340 ppb
2016-07-18CRCW071816M508ND
2016-07-18HBCB071816M508ND
2016-10-25HBCB102516M508ND
2016-10-25CRCW102516M508ND
2017-05-19AC980450.930 ppb
2017-05-19AC980440.680 ppb
2017-06-21AC990380.480 ppb
2017-06-21AC990390.560 ppb
2017-09-11AD074420.500 ppb
2017-09-11AD074430.530 ppb
2017-10-31CRCW103117M508ND
2017-10-31HBCB103117M508ND