Occurrence, Contamination, Speciation and Analysis of Selenium in the Environment

Abstract

Selenium (Se) is an essential micronutrient for animals and human. It serves as an antioxidant and anti-carcinogenic agent in humans. However, there is only a minuscule gap in intake concentration between deficiency and toxicity limits. Natural source of Se in the environment is due to weathering of selenium-containing parent bedrocks and atmospheric deposition. However, the magnitude of the release of Se into the environment has intensified by anthropogenic activities. The bioavailability and toxicity of Se depend on its chemical forms, exposure time, and concentration. Several studies have documented both the beneficial and adverse effects of Se on human and other biotic forms. In this context, understanding the fundamentals of selenium chemistry, occurrence, sources, toxicity, and exposure mechanism are important to control its intake and threshold uptake limit. The chapter reviews the literature relevant to the release of Se into the natural habitat, speciation, and its effects on humans and animals. The manuscript also renders outline on analytical techniques based on speciation and detection of selenium compounds.