Know Your Environment. Protect Your Health.

Selenium

San Andreas Mutual Water Company

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
20180.203 ppb31ND - 0.610 ppb
2019N/A00N/A
2020N/A00N/A
20212.37 ppb331.40 ppb - 3.30 ppb
2022ND30ND
20230.767 ppb32ND - 1.20 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2018-10-01CA4400558_001_001-2018100113300.610 ppb
2018-10-01CA4400558_003_003-201810011345ND
2018-10-01CA4400558_005_005-201810011400ND
2021-01-06CA4400558_003_003-2021010611203.30 ppb
2021-01-06CA4400558_005_005-2021010611232.40 ppb
2021-01-06CA4400558_001_001-2021010611151.40 ppb
2022-02-01CA4400558_001_001-202202011000ND
2022-02-01CA4400558_003_003-202202011005ND
2022-02-01CA4400558_005_005-202202011010ND
2023-01-16CA4400558_005_005-202301160950ND
2023-01-16CA4400558_001_001-2023011609401.20 ppb
2023-01-16CA4400558_003_003-2023011609451.10 ppb