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EWG's Tap Water Database — 2021 UPDATE

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Selenium

Westford Water Department

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.

 

12

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND20ND
2015ND20ND
2016ND20ND
2017ND20ND
2018ND20ND
2019ND20ND

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 Result
2014-06-11ND
2014-06-11ND
2015-05-04ND
2015-05-04ND
2016-04-05ND
2016-04-06ND
2017-05-24ND
2017-05-24ND
2018-05-15ND
2018-05-16ND
2019-05-01ND
2019-05-01ND