Heavy metals in the soil come from the weathering of the source rocks, especially those rich in sulfides, oxides, silicates, phosphates, and carbonates. They can also occur due to anthropic actions, such as the addition of fertilizers, pesticides, and waste disposal. The importance of the analysis of heavy metals is related to the fact that they are different from other toxic agents, because they are neither synthesized nor destroyed by man. But some metals are essential for the growth of all kinds of organisms, from bacteria to humans, but they are required at low concentrations because they can damage biological systems. Large amounts of metal can cause physiological changes, reduced vigor, and in extreme situations, the total inhibition of plant development, thus causing major disturbances in the ecosystem. This study was conducted in the Scientific Station Ferreira Penna, municipality of Melgaço, Pará-Brazil, in a YELLOW LATOSSOLO under tropical forest cover, aiming to determine the levels of heavy metals in these natural environments. Deformed soil samples were collected in two distinct periods: dry and rainy, in plots of 20mx20m, at depths: 0-15cm, lS-30cm and 30-50cm, using a "Dutchman" auger. The pH results (in H, o and KC1) were in the extremely acidic to strongly acidic range. The remaining data from this work are in progress in the laboratory.
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