What is Trace element?
A '''trace element''' is present in only a small amount. The amount depends on context. * In [[analytical chemistry]], it is an [[Chemical element|element]] in a sample that has an average [[concentration]] of less than 100 parts per million (ppm) measured in atomic count, or less than 100 [[microgram]]s per gram. * In [[biochemistry]], it is one that is needed in minute quantities for the proper [[growth]], [[development]], and [[physiology]] of the organism.<ref>H.J.M. Bowen 1976. ''Trace elements in biochemistry''. 2nd ed, Academic Press.</ref> In biochemistry, a trace element is also referred to as a ''micro[[nutrient]]''. See [[Enzyme#Cofactors|Cofactor]]. *In [[geology]], its concentration is less than 1000 ppm or 0.1[[%]] of a [[Rock (geology)|rock]]'s composition. The term is used mainly in [[igneous rock|igneous]] [[petrology]]. == References == {{reflist}} {{chem-stub}} [[Category:Biochemistry]] [[Category:Geology]]