Exposure to trace elements by hair mineral analysis. Mining , volcanic and urban areas

Abstract

Concerns about the effects of environmental exposure to metals and metalloids on human health have driven the scientific community to find reliable tools and methodologies for assessing the impact of emission of toxic metals from anthropogenic sources or through natural anomalous levels of metals in water, soil and air. Biological monitoring has been extensively employed with this end in view and blood, urine, hair and nails are the biological materials mostly collected and analyzed for the levels of multiple metals. With respect to blood and urine, whose metal concentrations decrease rapidly after the exposure period, hair and nails appear to be of greater value in evaluating past and continuous exposure to high levels of metals. The main goals of the present study regard the opportunity to evaluate the use of human hair as an alternative and non-invasive method of biomonitoring the expose to trace elements or to find, if existing, relationships between the trace element contents and lifestyle and atmospheric particulate matter or to characterize the hair concentrations of toxic, non-essential and essential chemical elements in young subject above all to create an extensive database of reliable reference ranges expected in different geographical and geochemical environments. The study provides data about trace elements in scalp hair samples from a total of 735 children, aged 11-13 years old, living in various geographical areas of Sicily (southern Italy) and Sardinia. 215 samples are from subjects living in the city of Palermo, 376 in Etna areas and 144 in the mineralized areas of Sulcis-Iglesiente. Nineteen elements (Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, U, V and Zn) were determined by inductively coupled mass spectrometry (ICP-MS). Mt. Etna is an important source of trace elements in the local environment, contributing approximatively 16% to the global budget during eruptive periods and approximatively 2% during normal degassing. The most abundant chemical elements were zinc and copper (Zn>Cu), with concentrations exceeding 10g/g. Other elements with concentrations greater than 1g/g were, in order of abundance, Al>Sr>Ba>Pb. The remaining elements were all below 1g/g. The Etna area has been subdivided in to three sectors in according to geological, geophysical and hydrogeologic characteristics. Significant spatial differences (p<0.05) in elemental concentrations were observed among the sectors. The northern sector generally has lower median values than the other two, for all variables. The eastern sector has higher median values for Cd, Mn, Pb and U, and the western one has higher values for As, Ba, Co, Cr, Li, Mo, Ni, Rb, Sb, Se and V. The Sulcis-Iglesiente district is one of the oldest and most important polymetallic mining areas in Italy, mining activity has released significant quantities of metals and metalloids in to the surrounding environment. To identify possible sources of metals and metalloids in hair samples a Principal Component Analysis (PCA) was used. The PCA identifies three factors: the first factor is composed of Ag, Ba, Cd, Cu, Ni, Pb, Sb, V and Zn , and PC1 reflects the influence of sulfides mineralization, the second indicates the strata- bound sulfides and includes Se, As, Cr and Fe and U and the last factor made up of Co, Ni and Sr. It may indicate other sources of metals such as carbonate rocks and coal deposits. In this study, the reference site is an environment which includes an urban area (Palermo town) and two suburban areas. The comparison shows that some elements are always found in similar concentrations and these elements are Zn, Cu, Al and Sr. the other elements in concentrations under 1ppm depend on the environment, in particular from the IG area were greater for some elements (Ag-Cd-Se-Pb-Ba) confirming their higher exposure to polymetallic contaminants. Trace element concentrations from the Etna area we