Know Your Environment. Protect Your Health.

Atrazine

Metropolitan Utilities District

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)

6

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND110ND
2019ND20ND
20200.0523 ppb73ND - 0.157 ppb
2021ND50ND
20220.117 ppb220.107 ppb - 0.126 ppb
20230.0498 ppb62ND - 0.203 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
2018-04-24543626ND
2018-04-24543624ND
2018-04-24543625ND
2018-06-05545300ND
2018-06-05545301ND
2018-06-05545297ND
2018-07-16560974ND
2018-08-28561294ND
2018-08-28561296ND
2018-08-28561293ND
2018-08-28561295ND
2019-04-29604248ND
2019-07-22621275ND
2020-04-20668338ND
2020-04-20668339ND
2020-04-206683370.104 ppb
2020-05-18676349ND
2020-05-186763370.105 ppb
2020-05-186763500.157 ppb
2020-08-03684325ND
2021-04-07727697ND
2021-04-07727698ND
2021-08-04753934ND
2021-08-04753930ND
2021-08-04746189ND
2022-04-197917240.126 ppb
2022-04-197917230.107 ppb
2023-01-17844826ND
2023-04-05855572ND
2023-04-05855571ND
2023-05-228562650.203 ppb
2023-07-25873789ND
2023-08-228744040.0960 ppb