Atributos e teores naturais de metais pesados em solos arenosos na Amazônia Central

Abstract

The growth of the urban, industrial and population areas of the Metropolitan Region of Manaus has increased the levels of heavy metals in the soils and impacted the quality of this resource. The environmental monitoring bodies need reference indicators for the continuous evaluation of environmental impacts, the reference values (VQR) are indicators of soil quality, obtained from the natural heavy metal contents present in the different soil classes of a region. The first chapter aimed to perform the morphological description and the classification of sandy soils in the Metropolitan Region of Manaus. Eight (8) soil profiles were used to characterize the morphological, physical, chemical and soil classification attributes. The soils were classified as typical Quartzarenic Orbital Neosol, Arsenic Quartzalic Neosol, Typical Quartzic Hydromorphic Neosol and Typical Distrópico Neosol. The second chapter aimed to determine the natural and VQR's of twenty (20) chemical elements in sandy soils of the Metropolitan Region of Manaus. For this, the total contents by acid attack, with digestion in microwave oven, were determined according to EPA 3051A of the Environmental Protection Agency (USEPA) and the contents by spectrophotometry of optical emission with induced plasma (ICP-OES). The contents of the heavy metals found in the studied soils followed the descending order: Al>Fe>Zn>Cr>Ni>Mn>Mo>Ba>Pb>Hg. The total contents extracted in sandy soils are relatively low and inferior to those reported for VQR's, Values of Prevention (PV) and Investigation Values (VI) of soils of the State of Amazonas, CONAMA and other Brazilian regions.