Natural backgrounds and reference values of trace-element in earth murundus fields on the Southern Amazon

Abstract

Earth mounds fields are wetlands characterized by having a plan relief interspersed with mounds. The knowledge of the levels of trace elements in this environment is important to support sustainable management in areas subject to human intervention in order to reconcile the productive demand and environmental conservation. The objective of this study was to determine the levels and establishing baseline values for trace elements (Zn, Ni, Cu, Cr, Pb, As, Cd, and Se), Fe and Mn in the earth mounds fields soils on the southwest region of the Mato Grosso State. For this soil samples were collected at the depth of 0 to 20 and 20 to 40 cm in “murundus” and “flat” environments, which represent the mounds themselves and the area around it, respectively. The proposition of baseline values was performed according to Conama Resolution 420/2009. The baseline values proposed for these environments were: Zn 7.8; Ni 6.0; Cu 9.2; Cr 21.0; Pb 10.8; As 1.6; Cd <0.03; Se <0.31 and Mn 16.5 mg kg-1 and Fe 4.9 g kg-1. The levels observed reflect the poverty of the source materials of these soils in these elements, as well as the absence of contamination.