Selenium in Drinking Water Information:

Properties:

Selenium is a nonmetal and that be a range of different colours in its elemental form; depending on the way the selenium atoms pack together and arrange themselves, the colour of the element can be black, grey, or red. Selenium rarely exists as a pure element in nature. Instead, it forms compounds with different atoms and metals and can be present in a variety of soils, rocks, and minerals. Selenium, in trace amounts, is an essential nutrient for humans.1   

Sources:

The properties of selenium make it particularly useful in a wide range of applications. The most common of these include electronics, photographic devices, plastics, anti-dandruff shampoo, supplements, fungicides, and glass.2 In general, selenium sources that create cause for concern in drinking water are the result of anthropogenic activity. For example, industrial run-off and the burning of coal can increase concentrations of selenium in raw water samples.3

Regulations:

The limit for selenium in drinking water is 10 micrograms per litre (µg/L).  

Health/Environmental Concerns:

Although selenium is an essential nutrient, it still acts as a toxin if excess quantities are ingested or absorbed in the body. Dangerous levels of selenium in drinking water are rare, but symptoms such as hair loss, brittle/deformed nails, and mental problems may occur.1 Selenium has also been linked to gastrointestinal issues, dermatitis, and dizziness.3

Action:

Proximity to industrial plants can increase the risk of selenium exceedances, and it can be beneficial to have levels checked if you have any concerns about raw water quality. Methods to remove selenium from water include coagulation and activated alumina absorption.3 Contact your Water Service Authority if you have any concerns. If drinking water makes you sick, see a doctor right away.

1 Guidelines for Drinking Water Quality. Selenium in Drinking Water; Vol. 2; World Health Organisation: Switzerland, 1996.

2 Toxicological Profile for Selenium; Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services: Atlanta, GA, 2006. 

3 Guide to the Parameters in the European Communities. What’s in your water?; S. I. No. 278 of 2007; National Federation of Group Water Schemes: Ireland.