Scalp hair analysis as a tool in assessing human exposure to heavy metals (S. Domingos mine, Portugal).

Hair samples from the scalp were used in a preliminary assessment of heavy metals exposure (As, Cd, Cr, Cu, Mn and Zn) of the human population living near an abandoned cupric pyrite mine (Mina de S. Domingos, Southeast Alentejo, Portugal). In parallel with the collection of hair samples, individuals from two different communities at the South and North of the mine area answered a questionnaire designed to obtain information about potential exposure pathways to these elements. The questionnaire allowed data collection about the most frequently consumed foodstuffs, drinking water sources, smoking habits, alcohol consumption and health condition. Higher concentrations, and subsequently higher ranges, of Cd, Cu and As were recorded in individuals living near the mine (MSD group), in opposition to individuals living several kilometers apart. Additionally, the concentrations recorded in the hair of some individuals from the MSD group were above the reference values for non-exposed individuals, suggesting their enhanced exposure. However, no significant differences were found for the average concentration of these elements between villages. Individuals from the CP and SC groups presented significantly higher concentrations of Zn and Mn in scalp hair. These results were in agreement with the concentrations of these elements recorded in soil samples. The water supplies of the area do not seem to be potential sources of trace elements for human beings. In opposition, individuals that frequently consume milk and cheese obtained from cattle that usually breeds in the area presented significantly higher concentrations of As and Mn in their scalp hair. Our results suggest that the population of S. Domingos mine area and neighbour localities may be exposed to some of the elements analysed namely Mn and Zn. The most likely exposure pathways seemed to be animal foodstuffs, however, a more detailed analysis of these products, as well as garden vegetables and fruits, should be performed.