Selenium

What is Selenium?
Selenium is a metal found in natural deposits such as rocks. Selenium is essential in the diet however it is toxic at high levels. It is widely used in Industry, e.g. in the areas of electronics and photography. Selenium is released from natural and human-made sources, with the main source being the burning of coal. The major use of Selenium is in the manufacture of electronic components and in photography. Selenium compounds are used in some insecticides. In the drinking water regulations, it is defined as a Chemical parameter.
What is an exceedance of Selenium?
The limit set out in the drinking water directive for Selenium is 10?g/l. Therefore, any result above this level is an exceedance for Selenium.
How would an exceedance for Selenium occur?
An exceedance for Selenium in drinking water typically indicates that the water source is contaminated, either from natural sources (rock etc.) or from an industrial spillage.