Know Your Environment. Protect Your Health.

Atrazine

Harris County Municipal Utility District 23

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.

 

12

Samples

0

Samples exceeding legal limit (MCL)

3

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND20ND
2019ND20ND
20200.120 ppb21ND - 0.240 ppb
20210.0700 ppb21ND - 0.140 ppb
2022ND20ND
20230.0650 ppb21ND - 0.130 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2018-02-08AE13108ND
2018-02-08AE13129ND
2019-02-25AE55741ND
2019-11-19AE89832ND
2020-03-11AF023660.240 ppb
2020-03-11AF02367ND
2021-01-13AF392490.140 ppb
2021-01-13AF39250ND
2022-01-25AF81765ND
2022-12-19AG22228ND
2023-01-17AG248220.130 ppb
2023-04-06AG35945ND