Homogeneização e níveis de metais em dejetos provenientes da bovinocultura de leite

The objective of the present work was to determine the homogenization time so that the metals Cu, Zn, Fe, Mn, Cd, Pb and Cr would show the highest uniformity in a reservoir of bovine manure, as well to determine the concentration of this metals in the manure. Samples of the manure in four different times of homogenization and in three different depths were collected. The experimental design used was of subdivided parcels. The parcel was formed by the depth of collecting samples, and the sub parcel by the collecting times. The determination of metals was performed by flame atomic absorption spectrometry. The found concentrations of metals in the manure were lower than the established limits, and the necessary time for the homogenization of Cu, Zn and Mn is 50 minutes; for the Cd, Pb and Fe is 30 minutes and for the Cr 60 minutes.