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EWG's Tap Water Database — 2019 UPDATE

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Atrazine

Rathbun Regional Water Assn

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.

 

15

Samples

0

Samples exceeding legal limit (MCL)

11

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.400 ppb440.300 ppb - 0.500 ppb
20130.200 ppb42ND - 0.600 ppb
20140.450 ppb220.400 ppb - 0.500 ppb
20150.200 ppb110.200 ppb
2016ND20ND
20170.500 ppb220.500 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
2012-03-0118894080.400 ppb
2012-06-0419081640.300 ppb
2012-09-1019299590.400 ppb
2012-12-0319483310.500 ppb
2013-03-0419647550.600 ppb
2013-04-091973632ND
2013-06-111984289ND
2013-06-1119842880.200 ppb
2014-01-0720264800.500 ppb
2014-04-0220437040.400 ppb
2015-04-07OE2285770.200 ppb
2016-04-06OE363037ND
2016-04-06OE363051ND
2017-03-15OE4912520.500 ppb
2017-04-10OE4998790.500 ppb