Читать книгу Selenium Contamination in Water - Группа авторов - Страница 32

Selenium (Se) is considered to be a vital element for living organisms. In 1817 a Swedish chemist, Jo¨ns Jakob Berzelius, discovered this element during sulfuric acid production. The name given was complementary to its sister element tellurium. The meaning of tellurium in Greek is “earth” and selenium is named after the Greek moon goddess, Selene. As Se is an essential micronutrient, its importance has been grown widely in recent years. The global estimates state that approximately 3000 million population of the world suffer from Se deficiency and are prone to the various health impacts. The Se‐deficient countries reported so far include USA, Canada, Japan, China, Finland, Scotland, New Zealand, and Spain (Fordyce 2013). Se requirements in human and animals can be met by consuming food which contains Se. Consumption of crops such as cereals, wheat, and vegetables which contain Se in small concentrations can fulfill the Se requirement of a whole population (Awika 2011). The presence of Se in human populations is majorly dependent upon the level in soil and food that is being produced in such soil. The addition of Se in the food chain is desirable and acceptable when it is in low concentration; however, the increased level of Se leads to an adverse effect on the human population and environment (Rayman 2008).

Dietary Se in human and animals has its own advantages, but overconsumption or exposure can lead to harmful effects. Concentration and speciation of the Se is the deciding factor for the impact of Se on environment. There is a great amount of literature available on Se which majorly focuses on nutrition and its occurrence in food chain. In recent years Se has emerged as a pollutant which may contaminate and cause severe toxicity to the environment. Researchers have started evaluating the occurrence, sources, and harmful effect of Se and are working on different mitigating, removal, and remediation technologies. Brief insights into Se as an emerging contaminant in water and soil are covered in this chapter, along with its natural and anthropogenic sources and uses.