Lead isotopes in biological matrices to identify potential sources of contamination: the case study of Sulcis-Iglesiente district (SW Sardinia, Italy)

The Sulcis-Iglesiente district has been, until recently, one of the most important Italian polymetallic mining areas for the extraction of lead. Located close to the town of Iglesias, the San Giorgio area constitutes a dramatic example of an area affected by intense mine pollution. Epidemiological studies regarding the mining areas of Sardinia have indicated the Sulcis-Iglesiente as a typical example of how dispersion of metal can affect human health. We have chosen this peculiar area to evaluate whether a supposed prolonged and continuous exposure to high lead concentration can be detected by means of a bio-monitoring procedure that uses the analysis of human scalp hair and the measurement of lead isotope ratios. Total lead concentrations in 144 human scalp hair samples from adolescents (11–13 years old) belonging to both genders, along with 23 lead isotope analyses in hair samples from Sant’Antioco (10 samples), Iglesias (10 samples) and roadway dust (3 samples) are discussed here. The hair database consisted of two groups of samples: 1) Iglesias group (IG) consisting of 59 subjects (32 females and 27 males). The town of Iglesias is located near the mining–waste of San Giorgio area. Other potential local pollutants are limited to emissions from vehicular traffic. 2) Sant’Antioco group (SAN) containing 85 cases (52 females and 33 males). The area of Sant’Antioco Island is not affected by intense mine activity and the pyroclastic volcanic rocks, outcropping in this site, are not characterised by metal mineralisation events. Three road dust samples were collected; two close to the mining area, more precisely one at Monteponi (RDMT), and another one within the urban area of Iglesias (RDIG) and a third sample was collected at Sant’Antioco, an area affected by industrial activities. Pb concentrations of adolescents living at Iglesias resulted higher than those of adolescents living at Sant’Antioco (median values PbIG: 1.56 μg/g and PbSAN: 0.30 μg/g, respectively). The influence of gender did not play any significant ...