Lanthanides, Actinides and other Elements in the Atmospheric Fine and Coarse Fractions by INAA

Among the various species present in the particulate matter composition, a greater is devoted to study elements at elevated toxicity and wide diffusion in environment (e.g., Cd, Cr, Ni, Pb, Zn, etc). Considering that an important target in the atmospheric pollution evaluation is the acquisition of knowledges related to understand levels and behavior of elements toxicologically and geochemically important, in the last years a particular interest is assuming the determination of some elements of which few data exist in literature and that only recently they are considered in certain important industrial processes. Particularly, some precious metals such as Pd, Rh, Ir finding large usage in catalytic pots and rare earths such as Sm, Us, Eu used in optical fibres and in electronics, must be considered. In this paper we have applied a nuclear technique, i.e. Instrumental Neutron Activation Analysis (INAA), for studying the metal composition in fine and coarse fractions. This nuclear technique allows the determination of about 25 elements: for some of them this is the first determination in the ambient air of Rome and particularly for lanthanides and actinides. The main results (min and max values) are reported and they can be considered representative of Rome. Basically, more elevated distribution in the coarse fraction than in the fine fraction whereas only few elements show a very good distribution between the two fractions (i.d., Br, Fe, Sb). No good correlation between the two fractions is shown by elements such as Ce (natural origin), Cs (no influence by marine air stream), Sc (natural origin and no industrial uses) and Th (consistent variability between summer and winter). From a toxicological point of view, no significant level of attention was found.