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EWG's Tap Water Database — 2019 UPDATE

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Selenium

City of Mesa

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.

 

67

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.355 ppb3110ND - 2.00 ppb
20131.000 ppb21ND - 2.00 ppb
20142.00 ppb112.00 ppb
20150.0580 ppb301ND - 1.74 ppb
20160.950 ppb21ND - 1.90 ppb
20172.00 ppb112.00 ppb

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
2012-04-0912040135ND
2012-04-1612040144ND
2012-05-07201205240371IND
2012-05-08201205240373IND
2012-05-0812040145ND
2012-08-0612070773ND
2012-08-06120707761.000 ppb
2012-08-0612070782ND
2012-08-0712070775ND
2012-08-0812070787ND
2012-08-08120707841.000 ppb
2012-08-08120707741.000 ppb
2012-08-13120707351.000 ppb
2012-08-1312070733ND
2012-08-1312070714ND
2012-08-1412070732I1.000 ppb
2012-08-1412070715ND
2012-08-1412070736ND
2012-08-1512070771ND
2012-08-15120707341.000 ppb
2012-08-1512070716ND
2012-08-22120707861.000 ppb
2012-08-22120707831.000 ppb
2012-08-2212070778ND
2012-08-2712070779ND
2012-08-2712070772ND
2012-08-2712070777ND
2012-08-2812070785ND
2012-08-2812070781ND
2012-09-24120707801.000 ppb
2012-11-20121106192.00 ppb
2013-07-1613070278ND
2013-10-14131004952.00 ppb
2014-10-08141002972.00 ppb
2015-04-0715040273ND
2015-04-0715040272ND
2015-04-07150402491.74 ppb
2015-04-1415040400ND
2015-04-2115040606ND
2015-04-2815040768ND
2015-04-2915040772ND
2015-04-2915040771ND
2015-07-0615070077ND
2015-07-0615070073ND
2015-07-0615070074ND
2015-07-0615070076ND
2015-07-0715070120IOCND
2015-07-0715070119IND
2015-07-0715070117ND
2015-07-1315070251ND
2015-07-1315070247IND
2015-07-1315070249ND
2015-07-1315070250ND
2015-07-1415070255ND
2015-07-1415070254ND
2015-07-1415070253ND
2015-07-1415070252IND
2015-07-2015070391ND
2015-07-2115070451ND
2015-07-2115070450ND
2015-07-2115070449ND
2015-07-2115070448ND
2015-07-2115070447ND
2015-07-2715070541ND
2016-06-0816060165IND
2016-10-04161000391.90 ppb
2017-10-10171004012.00 ppb