Determinação dos metais presentes no material particulado atmosférico da região urbana de Manaus

Abstract

Exposure to airborne particles and substances associated with them can cause deleterious effects to human health, flora, fauna and the monuments and buildings in general. So monitor the airborne particles in atmospheric air is important to ensure the health and welfare of the population. In Brazil, there are values established for air quality standards for total suspended particulates (TSP) and PM10. But there is no values established for the chemical constituents of these particles. This study aimed to determine the presence of metals in the airborne particulate matter (PM) suspended in some regions of the urban area of Manaus. Was promoted to collecting MP in three regions of Manaus, defined as vehicular area, industrial area and residential area between February and April (rainy season) and between August and October (dry season) 2013, plus the “background” a forest reserve distant 26 km from the city, being, therefore, a reference point to be used as compared for the urban atmosphere of the city of Manaus. The metals determined in PM, were: Cr, Cu, Fe, Mn, Ni, Pb and Zn. The collection of PM was performed by the method of active sampling in the holder type samplers with Teflon membranes. Detection of metals was made with application of atomic absorption spectrometry by two types of atomization, flame and electrothermal atomization (FAAS and GFAAS). The results demonstrated the predominant presence of Fe, Zn and Pb in all regions studied. Three main sources were assigned to Fe: soil resuspension in residential areas and background, and in the other regions: industrial activities and vehicular traffic. For Zn did not possible to determine a defined spatial distribution. Regarding Cu, Mn and Pb, the regions residential and background showed similarity, but were different from industrial and vehicular areas, especially in the dry season. Seasonal evaluation of the data have not shown any difference between the rainy and dry seasons, indicating that the weather conditions had no significant influence on the presence of metals in airborne particulate matter from Manaus during this period. Probably emission sources have the greatest effect ou the metal concentrations at the atmosphere. The median concentrations of metals found in the samples of particulate matter were lower than the standards proposed by international entities and institutions (EPA, ASTDR and WHO), as well as when compared to studies on other cities in the country.