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EWG's Tap Water Database — 2021 UPDATE

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Selenium

Dtma Main System

Selenium is an essential element in diets. But too much selenium can decrease thyroid hormone production and cause hair loss, skin lesions and brittle fingernails.

 

21

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015ND110ND
2016N/A00N/A
2017N/A00N/A
2018ND100ND
2019N/A00N/A

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 30 ppb

The EWG Health Guideline of 30 ppb for selenium 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 hair loss and nail damage.

EPA Maximum Contaminant
Level (MCL) 50 ppb

The legal limit for selenium, established in 1991, was based on human epidemiological studies of populations exposed to naturally occurring selenium in drinking water. This limit does not include any additional consideration of children’s health.

ppb = parts per billion

All test results

Date Lab ID Result
2015-08-1813125649ND
2015-08-1813125820ND
2015-08-1813125787ND
2015-08-1813125775ND
2015-08-1813125763ND
2015-08-1813125730ND
2015-08-1813125718ND
2015-08-1813125706ND
2015-08-1813125694ND
2015-08-1813125661ND
2015-08-1813125637ND
2018-09-212340209002ND
2018-09-212340210001ND
2018-09-212340210002ND
2018-09-212340208002ND
2018-09-212340207001ND
2018-09-212340206002ND
2018-09-212340209001ND
2018-09-212340207002ND
2018-09-212340208001ND
2018-09-212340206001ND