Total element concentration and chemical fractionation in airborne particulate matter from Santiago, Chile

Abstract

Total element determination and chemical fractionation were carried out in airborne particulate matter (PM10) from the Cerrillos monitoring station in Santiago, Chile, sampled in July (winter), 1997-2003. Element concentration in the period under study (1997-2003) was statistically analyzed through cluster analysis in order to identify groups of elements having similar behavior along time. Elements such as Cd, Cu, Pb, Ni, As and Mg show a clear decrease in concentration with time. On the contrary, chromium increases its concentration almost linearly during the period. In order to estimate whether the presence of a certain element in PM10 matrix is mainly due to anthropogenic or natural processes, the enrichment factor of each element was determined. According to their behavior in the sequential extraction procedure, the elements were grouped by multivariate analysis in three clusters: (a) those mobile elements (Pb, Cd, Zn, Mn, Cu and As) which are weakly bound to the matrix (fractions 1 and 2) (b) those elements (V, Ti, and Cr) mainly bound to carbonates and oxides (fraction 3) and (c) the most immobile elements (Ni, Mo, Ca, Mg, Ba and Al), mainly bound to silicates and organic matter (fraction 4). A source of great concern is the fact that elements of such high toxicity as Pb, Cd and As are highly concentrated in both mobile fractions, indicating that these elements have a direct impact on the environment and on the health of the exposed population.