CRITICAL COMPARISON BETWEEN VOLTAMMETRIC AND SPECTROSCOPIC TECHNIQUES FOR THE DETERMINATION OF HEAVY METALS AND PLATINUM GROUP METALS (PGMS) CONCENTRATIONS IN ITALIAN AIRBORNE PARTICULATE MATTER

Recently, pollution linked to airborne particulate matter has drawn attention. The issue is due to a drastic increase of anthropic activities: industrial activities, in all their different typologies, and more and more increasing vehicular traffic. As a consequence, the totality of the pollutants associated with the various types of particulate are everywhere strictly dependent on the type of source of the same particulate. Moreover, the particle size evidently has a particular importance, since the decrease of the aerodynamic diameter of particulate corresponds to greater ease of penetration of the same particulate in the deeper levels of the respiratory system. This obviously is a serious problem for human and animal health, implying high costs in health care. Due to multiple simultaneous sources in areas at high anthropic impact, there are many pollutants associated with airborne particulate matter, both of inorganic and organic kind, and even simultaneously present on the same particulate samples. In any case, the pollutant determination in airborne particulate matter certainly must be accurate, reproducible and it must be especially characterized by very low limits of detection. In particular, the present work reports and discusses the different analytical procedures for the voltammetric and spectroscopic determination of heavy metals and metalloids (copper, lead, cadmium, zinc, mercury, tellurium, arsenic, selenium, tin, antimony, vanadium, nickel, chromium) in airborne particulate matter sampled in two sites, differently influenced by anthropic pollution. An additional sampling, carried out in a zone at very low anthropic impact, was chosen for eventual comparisons. The chosen particulate-matter size was PM2.5 (aerodynamic diameter < 2.5 µm) even if the proposed methodologies evidently can be also applied to all other particle sizes of interest. A separate section will be dedicated to the analytical procedure for the determination in airborne particulate matter of new emerging anthropic polluting traffic-related pollutants, i.e. the platinum group metals (PGMs) — platinum, palladium, rhodium, osmium, ruthenium and iridium — that, in the last decade, have aroused much interest from scientific community