Chemical fractionation of heavy metals in airborne particulate matter (PM10) by sequential extraction procedure

Abstract

In this study, a series of 36 airborne particulate matter (PM10) samples were colleted over a 1 year period at an urban area–Tirupati, India. The samples were collected on paliflex-filters using Mini-Partisol air sampler equipped with PM10 inlet. A three stage sequential extraction procedure viz. environmentally mobile, bound to carbonates and oxides and bound to silicates and organic matter, was applied to heavy metals such as Pb, Cd, Zn, and Cu in PM10 samples. The heavy metals were determined by differential pulse anodic stripping voltammetry (DPASV). The reliability and applicability of the method was checked by using, NIST Standard Reference Material (SRM 1648). Good agreement was obtained between the total concentration of studied metals after three-step leaching procedure and certified values. Speciation results shows that higher percentage of Pb and Cd are accumulated in mobile fraction, where as higher amount of Cu and Zn was found in environmentally immobile fraction. Multivariate statistical analysis has been performed for the variables to define possible sources, and the results shows that mainly two sources, particles from traffic and particles from land were identified.