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EWG's Tap Water Database — 2021 UPDATE

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Heptachlor epoxide

Castle Rock

Heptachlor epoxide is a breakdown product of heptachlor, a highly toxic and carcinogenic pesticide banned in the U.S. since the 1980s.

MORE ABOUT THIS CONTAMINANT

 

40

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND70ND
2015ND10ND
2016ND60ND
2017ND100ND
2018ND80ND
2019ND80ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.006 ppb

The EWG Health Guideline of 0.006 ppb for heptachlor epoxide was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL) 0.2 ppb

The legal limit for heptachlor epoxide, established in 1991, was based on analytical detection limits at the time that the standard was set. This limit may not fully protect against the risk of cancer.

ppb = parts per billion

All test results

Date Result
2014-02-26ND
2014-04-29ND
2014-07-21ND
2014-07-22ND
2014-11-19ND
2014-12-04ND
2014-12-04ND
2015-08-05ND
2016-02-23ND
2016-02-24ND
2016-05-23ND
2016-06-27ND
2016-07-18ND
2016-11-14ND
2017-02-21ND
2017-02-21ND
2017-03-22ND
2017-04-18ND
2017-04-18ND
2017-05-16ND
2017-06-21ND
2017-07-17ND
2017-07-17ND
2017-10-18ND
2018-03-20ND
2018-03-20ND
2018-05-21ND
2018-08-30ND
2018-09-13ND
2018-11-16ND
2018-12-12ND
2018-12-12ND
2019-02-07ND
2019-04-17ND
2019-09-16ND
2019-09-16ND
2019-11-05ND
2019-11-25ND
2019-12-11ND
2019-12-11ND