Concentrações naturais de metais e contribuição de dejetos de suínos na disponibilidade de Cu e Zn em solos do polo suinícola do estado de Mato Grosso

Abstract

The growth of pig farming activity in the state of Mato Grosso has been significant, in 2021 the pig herd increased by 27% compared to the last five years. The disposal of waste from this activity as a source of fertilizer in crops has raised environmental concerns, due to the increase heavy metal concentrations when improperly disposed. One of the alternatives for monitoring these areas is the knowledge of the natural concentrations of heavy metals in soils under native areas close to the waste application areas, in order to obtain reference values ​​and soil quality guidelines for the Sunicola Mato Grosso Complex. Obtaining Soil Quality Reference Values ​​(VRQ) has a legal provision that also provides for values ​​for preventing investigation of contaminated areas. Due to the lack of regulation and standardization of VRQs by the competent environmental agency of Mato Grosso, and the need to evaluate the concentrations of Zne Cu in areas under application of swine manure, this study aimed to: (1) Determine the natural concentrations of Cd . Cu, Mn. Ni, Pbe Zn and evaluate the correlations with the attributes (pH, CTC, FeO ALO, MO, site clay and sand) of the native soils of the Suinicola Poles of the State of Mato Grosso: (2) and verify the availability of Copper (Cu) and Zinc (Zn) available soils under different application times of swine waste and evaluate the correlations with the attributes (pH, СТС, Ге:О, АБО MO, clay, fine sand). The extraction of Cd, Cr, Cu, Mn, Ni. Pb and Zn was done using the USEPA 30508 method, and extraction of available Cu and Zn, areas that received waste, was done using the Mehlich-1 double acid extractor. The natural concentrations of reference soils are lower when compared to some guiding and reference values of Brazilian States and well below the prevention values ​​of the Conama resolution. 420/2009 and followed in descending order. Mn Cr Pb>Zn>Ni>Cu>Cd. With the exception of Cd, there were significant correlations between heavy metals, and between Cr, Cu, Mn, Ni. Ph with the argy fraction, organic matter, CEC and soil pH. In the areas under application of swine manure, available Cu and Zn levels were high in the arable layer, and positively correlated with the acid pH of the soil. Zn preferentially correlated clay fraction and iron oxides. Cu positively correlates with the long application time of pig manure (24 years), mainly in areas with sandy soils.