Know Your Environment. Protect Your Health.

Atrazine

Hillsboro

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.

 

23

Samples

0

Samples exceeding legal limit (MCL)

10

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.385 ppb43ND - 0.680 ppb
20190.493 ppb42ND - 1.40 ppb
20200.173 ppb31ND - 0.520 ppb
20210.245 ppb42ND - 0.490 ppb
20220.118 ppb41ND - 0.470 ppb
20230.0775 ppb41ND - 0.310 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
2018-02-128021864-010.410 ppb
2018-06-048061040-010.450 ppb
2018-08-078082263-010.680 ppb
2018-10-248105214-01ND
2019-03-119031951-01ND
2019-04-169043720-01ND
2019-09-129092559-011.40 ppb
2019-11-129111846-010.570 ppb
2020-01-020011450-01ND
2020-07-290076108-01ND
2020-10-130102839-010.520 ppb
2021-01-13EA02309-010.490 ppb
2021-05-18EE03572-01ND
2021-07-22EG04639-010.490 ppb
2021-11-15EK03576-01ND
2022-01-04FA00411-01ND
2022-04-20FD04172-01ND
2022-09-15FI03135-01ND
2022-11-01FK00984-010.470 ppb
2023-02-16GB03257-01ND
2023-06-20GF03961-01ND
2023-08-17GH03915-01ND
2023-10-19GJ03799-010.310 ppb