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EWG's Tap Water Database — 2021 UPDATE

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Selenium

City of Merced

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.

MORE ABOUT THIS CONTAMINANT

 

60

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND200ND
2015N/A00N/A
2016ND200ND
2017ND10ND
2018N/A00N/A
2019ND190ND

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
2014-01-095810-008-0832ND
2014-01-095810-020-0937ND
2014-01-095810-019-1109ND
2014-01-095810-022-1250ND
2014-01-095810-016-1350ND
2014-01-095810-023-0900ND
2014-01-095810-015-1430ND
2014-01-095810-041-0955ND
2014-01-095810-011-1445ND
2014-01-095810-042-1053ND
2014-01-095810-043-1031ND
2014-01-095810-005-0857ND
2014-01-095810-048-1409ND
2014-01-095810-004-0854ND
2014-01-095810-049-1140ND
2014-01-095810-054-1318ND
2014-01-105810-002-0950ND
2014-01-105810-003-0941ND
2014-01-105810-001-0944ND
2014-01-105810-021-0858ND
2016-05-101233-057-1600ND
2016-09-019590-001-1205ND
2016-09-019590-002-1400ND
2016-09-019590-003-1255ND
2016-09-019590-054-0846ND
2016-09-019590-004-1240ND
2016-09-019590-049-0945ND
2016-09-019590-005-1340ND
2016-09-019590-048-0910ND
2016-09-019590-043-1235ND
2016-09-019590-020-1120ND
2016-09-019590-011-0901ND
2016-09-019590-041-1020ND
2016-09-019590-015-0810ND
2016-09-019590-023-1430ND
2016-09-019590-016-1030ND
2016-09-019590-022-1335ND
2016-09-019590-019-1055ND
2016-09-019590-021-1450ND
2016-12-019590-042-0854ND
2017-03-099590-008-0840ND
2019-08-065810-042-0845ND
2019-08-065810-049-1030ND
2019-08-065810-048-0755ND
2019-08-065810-043-1000ND
2019-08-065810-016-0820ND
2019-08-065810-054-1100ND
2019-08-085810-019-0820ND
2019-08-085810-020-0915ND
2019-08-085810-021-0725ND
2019-08-085810-041-0855ND
2019-08-135810-022-0725ND
2019-08-135810-023-0855ND
2019-08-135810-015-0955ND
2019-08-135810-005-0850ND
2019-08-135810-004-0830ND
2019-08-135810-003-0747ND
2019-09-195810-001-1230ND
2019-10-035810-011-1220ND
2019-11-265810-008-0825ND