How strongly are heavy metals correlated with soil attributes in tropical soils, and are their levels environmentally safe?

The mineralogical, physical, chemical, and electrochemical properties of the soil affect heavy metal availability. The correlation between metals and soil attributes provides insights into their availability and potential soil contamination. The aim of this study was to determine the levels of heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) and to evaluate the correlations with the attributes (pH, CEC, Fe2O3, Al2O3, organic matter (OM), clay, silt and sand) of tropical soils (native soils of the Swine hub of the State of Mato Grosso). Statistical analysis of the data wasused: Pearson's correlation, Principal Component Analysis and Canonical Discriminant Analysis. The concentrations of heavy metals (Mn>Cr>Pb>Zn>Ni>Cu>Cd) found varied according to the geomorphological and pedological differences. A correlation was observed between heavy metals (Cu, Zn, Ni, Cr and Mn) and soil texture as well as Fe and Al oxides. The clay and medium-clay texture correlated positively with the metals, while the sandy texture correlated negatively. A positive correlation was observed between OM and Zn, Ni, and Cr. Clayey tropical soils with higher OM show heavy metal affinity for soil colloids, reducing their solubility, mobility, and plant absorption. All measured levels were below CONAMA Resolution 420/2009, ensuring safety.