Coverage intervals for trace elements in human scalp hair are site specific

Coverage intervals for trace elements in human scalp hair commonly provide the basis for interpreting laboratory results and also in comparative decision-making processes regarding exposure risk assessment. This short communication documents, by some examples, that those computed for human hair are to be considered site specific, as they reflect local environmental conditions; also each geographic area has a typical profile of hair elemental composition of its inhabitants. Therefore, the levels of trace elements in hair are not strictly comparable between different areas of the world. This issue is particularly relevant when identification of anomalous environmental exposures are requested or even in detecting physiological disorders.