Know Your Environment. Protect Your Health.

Simazine

Harris County Water Control and Improvement District 89

Simazine is a hormone-disrupting herbicide related to atrazine. It affects the male and female reproductive systems. In studies of laboratory animals, simazine increases blood levels of estrogen, decreases prolactin and progesterone, and causes mammary and ovarian tumors.

 

12

Samples

0

Samples exceeding legal limit (MCL)

2

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND10ND
20190.110 ppb110.110 ppb
20200.0475 ppb42ND - 0.110 ppb
2021ND20ND
2022ND20ND
2023ND20ND

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 simazine 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): 4 ppb

The legal limit for simazine, established in 1992, was based on toxicity studies 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
2018-01-29AE11090ND
2019-02-19AE549270.110 ppb
2020-01-22AE94792ND
2020-04-22AF077630.110 ppb
2020-07-29AF211970.0800 ppb
2020-10-22AF31702ND
2021-02-23AF44013ND
2021-04-22AF51177ND
2022-01-31AF82681ND
2022-01-31AF82682ND
2023-03-07AG31981ND
2023-04-27AG38527ND