Selenium

City of Sherman

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

Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	2.75 ppb	2	2	1.10 ppb - 4.40 ppb
2015	2.40 ppb	1	1	2.40 ppb
2016	0.133 ppb	9	1	ND - 1.20 ppb
2017	ND	3	0	ND
2018	ND	1	0	ND
2019	ND	9	0	ND

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
2014-04-22	Q1412762003	4.40 ppb
2014-06-16	Q1421403005	1.10 ppb
2015-03-17	Q1509888004	2.40 ppb
2016-01-20	Q1602479019	ND
2016-01-20	Q1602479018	ND
2016-01-20	Q1602479017	ND
2016-04-11	Q1614214006	1.20 ppb
2016-11-08	Q1648503006	ND
2016-11-08	Q1648503005	ND
2016-11-08	Q1648503004	ND
2016-11-08	Q1648503003	ND
2016-11-08	Q1648503002	ND
2017-01-12	Q1701556004	ND
2017-01-12	Q1701556012	ND
2017-07-11	Q1728660017	ND
2018-07-05	Q1826605004	ND
2019-02-12	Q1906434014	ND
2019-02-12	Q1906434013	ND
2019-02-12	Q1906434012	ND
2019-02-12	Q1906434011	ND
2019-05-07	Q1922272015	ND
2019-05-07	Q1922272019	ND
2019-05-07	Q1922272018	ND
2019-05-07	Q1922272017	ND
2019-05-07	Q1922272016	ND