Distribution and availability of copper, iron, manganese and zinc in the archaeological black earth profile form the amazon region

Abstract

The archaeological black earth soils are rich in organic matter, contain ceramic fragments and lithics artifacts and feature nutrients in higher concentrations than other types of soils. To contribute information about micronutrient concentrations available in black earth soils, the distribution and availability of Cu, Fe, Mn and Zn in the archaeological black earth profile form the municipal district of Juruti, Pará State, was evaluated through sequential chemical extractions. The largest concentrations of Cu, Fe, Mn and Zn in the profile are found in the residual fraction. This study showed that the iron, manganese and zinc are preferentially available form the fractions associated with Fe-Mn oxides ranging form 1265.39 to 1818.12 mg kg-1, 0.83 to 48.51 mg kg-1 and 1.92 to 12.05 mg kg-1 respectively, and the copper form organic matter, ranging form 0.13 to 0.45 mg kg-1. © 2011 Sociedade Brasileira de Química.