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EWG's Tap Water Database — 2021 UPDATE

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Heptachlor

City of San Marcos

Heptachlor is an insecticide used for termite control until 1988. It is linked to cancer, hormone disruption and neurotoxicity.

 

40

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND50ND
2015ND50ND
2016ND90ND
2017ND80ND
2018ND60ND
2019ND70ND

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 0.008 ppb

The EWG Health Guideline of 0.008 ppb for heptachlor 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) 0.4 ppb

The legal limit for heptachlor, 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 due to heptachlor exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2014-03-12AC46849ND
2014-03-12AC46845ND
2014-08-12AC63192ND
2014-08-12AC63194ND
2014-08-12AC63193ND
2015-06-10AC95523ND
2015-06-10AC95525ND
2015-06-10AC95526ND
2015-06-10AC95524ND
2015-09-23AD08350ND
2016-03-16AD29232ND
2016-03-16AD29234ND
2016-06-16AD41044ND
2016-09-16AD49840ND
2016-11-28AD59251ND
2016-11-28AD59250ND
2016-11-28AD59249ND
2016-12-12AD61786ND
2016-12-12AD61785ND
2017-02-22AD71561ND
2017-03-23AD76702ND
2017-05-03AD82538ND
2017-05-03AD82539ND
2017-06-01AD86504ND
2017-07-12AD89117ND
2017-07-12AD89116ND
2017-10-12AE00643ND
2018-01-25AE10723ND
2018-01-25AE10725ND
2018-01-25AE10726ND
2018-01-25AE10724ND
2018-04-11AE22134ND
2018-07-26AE34744ND
2019-01-16AE50283ND
2019-01-16AE50279ND
2019-01-16AE50280ND
2019-01-16AE50281ND
2019-01-16AE50282ND
2019-04-16AE62665ND
2019-07-09AE73764ND