Determinação multielementar por ICP-MS em material particulado (PM10) coletado em área urbana de Belo Horizonte

Abstract

The aim of the study was to adapted and validate a method for multi-element analysis of metals in particulate material (PM10) by ICP-MS was applied for quantification of metals in samples collected at a fixed monitoring station in the urban area of Belo Horizonte between2013 and 2014. The evaluated elements were: Be, Li, V, Cr, Mn, Co, Ni, Cu, As, Se, Sr, Cd, Sb, Pb, U, Fe, Zn, Ba e Al. The samples were digested in a microwave with HNO3 50% v/v. The linear working range of the method was 100 µgL-1, with the exception of selenium thatshowed linearity up until 60 µgL-1. The detection limits were from 0.052 to 9.51 gL-1. Recoveries and accuracy were within the acceptance criteria of the AOAC (Association of Official Analytical Chemists) for the vast majority of elements. The results showed the presence of Chromium in two samples. According to WHO, there is no exposure limitconsidered safe for inhalation of Chromium, with Chromium (VI) being classified as a carcinogenic substance. Results were obtained for Manganese between 1.6-178 ng / m3. The WHO tolerance limit is 150 ng / m3 (annual average) and one of the samples (corresponding to one week) showed a concentration above this limit. For lead, tolerancelimit is 500 ng/m3 (annual average) and the values obtained were between 25.9-169 ng/m3. The elements that showed higher concentrations were Fe, Zn, Al and Ba. Literature studies infer that Iron and Manganese come predominantly from mining and steelmaking activities which are intense in the vicinity of Belo Horizonte. Sr and Al that presented a strong positive correlation of Pearson can originate from natural sources such as resuspension of soil dust and metallurgical industries. Sb, Pb, Cu, Cr and Zn are often attributed to vehicle emissions. Barium was mainly associated with the cement, lime and metallurgical industries. The multivariate statistical analysis showed a correlation between Fe and Mn, so that their concentrations vary inversely, that is, when one of them increases the concentration of the other decreases. It was also observed that in the months of February and March, in which there is a concomitant return of several activities that were in holiday recess there is an increase in the concentrations of elements related to automotive emissions (Cr, Pb and Zn) and some related to other activities, such as cement and metallurgical (Ba, Al, Sr).