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EWG's Tap Water Database — 2019 UPDATE

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Atrazine

City of South Houston

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.

 

33

Samples

0

Samples exceeding legal limit (MCL)

27

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.124 ppb550.1000 ppb - 0.140 ppb
20130.414 ppb550.390 ppb - 0.430 ppb
20140.134 ppb550.130 ppb - 0.140 ppb
20150.154 ppb770.120 ppb - 0.240 ppb
20160.0783 ppb63ND - 0.270 ppb
20170.260 ppb550.160 ppb - 0.330 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
2012-02-06AB802760.140 ppb
2012-02-06AB802750.1000 ppb
2012-02-06AB802710.110 ppb
2012-02-06AB802740.130 ppb
2012-02-06AB802670.140 ppb
2013-01-14AC076480.420 ppb
2013-01-14AC076490.420 ppb
2013-01-14AC076500.430 ppb
2013-01-14AC076440.410 ppb
2013-01-14AC076470.390 ppb
2014-01-14AC389030.140 ppb
2014-01-14AC389040.130 ppb
2014-01-14AC389080.130 ppb
2014-01-14AC389060.140 ppb
2014-01-14AC389050.130 ppb
2015-01-21AC771370.120 ppb
2015-01-21AC771310.130 ppb
2015-01-21AC771360.120 ppb
2015-01-21AC771290.130 ppb
2015-01-21AC771300.130 ppb
2015-09-15AD071800.240 ppb
2015-10-06AD096520.210 ppb
2016-01-14AD18395ND
2016-01-14AD18382ND
2016-01-14AD183850.1000 ppb
2016-01-14AD183880.1000 ppb
2016-01-14AD18391ND
2016-04-08AD326610.270 ppb
2017-01-06AD637560.160 ppb
2017-02-10AD704950.260 ppb
2017-03-01AD728800.260 ppb
2017-03-01AD728810.330 ppb
2017-03-01AD728790.290 ppb