4.1. Hair metal concentrations
Human biological monitoring has become an important tool in
environmental and public health for the assessment of internal doses to harmful substances (Gil and Hernández, 2009). Although blood and urine analysis are traditional approaches for biomonitoring, human hair is an interesting matrix because hair concentrations of metal compounds are up to 10-fold higher than the levels found in blood or urine samples. Hair testing can be used as a screening tool for biomonitoring chronic exposure to environmental toxic elements (Bencko, 1995). Nevertheless, there is controversy on whether the measurement of a substance in the hair