Physical properties and ion mobility assays in technosols designed for soil restoration of extractive activities

Abstract

The rehabilitation technologies in areas degraded by extractive activities require the use of their own mine spoils. Reducing deficiencies in bulk density and aggregate stability, organic matter, and nutrients with a contribution of treated sewage sludge is proposed. This experiment was based on a controlled study using percolation columns. The assays was done using two mine spoils, both very rich in calcite. Two sewage sludge doses were undertaken (30,000 and 90,000 kg/ha of sewage sludge compost) in addition to a different mine spoils used as substrates. Irrigation water was provided by a device that simulated short duration rain. The leached water was collected 24 hours after the last application. Electrical conductivity, pH and the ions nitrate, ammo-nium, phosphate, sulfate, and chloride were determined. The experiment saw the bulk density decrease and the aggregate sta-bility increase, thereby improving the structure. Significant nitrate concentrations appeared that may pose an environmental co-ntamination risk. The resulting values for each irrigation application, the relationship between parameters, and the environmental risk are discussed.