Methods of removing external metal contamination from hair samples for environmental monitoring

Human exposure to trace elements has become a major environmental issue with the growing industrialization and urbanization around the world. Hair samples are the most conveniently obtainable biopsy material and they have been identified as good indicators of the metal pollution in an environment. For their effective use, however, it is necessary to exclude the effect of external contamination of the hair surface by metals. The present investigation compares the different methods of washing hair samples prior to further treatment for elemental analysis. Deionized water, solvents (acetone, ether and carbon tetrachloride), non-ionic detergent, ionic detergent (sodium lauryl sulfate), chelating agent (EDTA-2Na), ultrasonics and combinations of these agents were used in the experiments. EDTA was found to be the most suitable of these washing agents for removing external contaminant metals. Further elucidation, however, is needed before a standard method of hair washing can be established.