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EWG's Tap Water Database — 2021 UPDATE

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Simazine

California Water Service (CWS) - King City

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.

 

16

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2013N/A00N/A
2014N/A00N/A
2015N/A00N/A
2016ND30ND
2017ND30ND
2018N/A00N/A
2019ND100ND

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 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
2016-03-079590-012-1143ND
2016-04-209590-006-1042ND
2016-09-209590-007-1117ND
2017-06-069590-014-1138ND
2017-06-069590-015-1105ND
2017-06-079590-008-1117ND
2019-03-069590-012-1227ND
2019-04-179590-006-1140ND
2019-06-039590-014-0940ND
2019-06-039590-015-1035ND
2019-06-049590-008-1026ND
2019-09-099590-007-1120ND
2019-10-219590-803-1009ND
2019-10-219590-804-1125ND
2019-10-229590-801-1038ND
2019-10-229590-802-1127ND