CADMIUM MOVEMENT THROUGH CALCAREOUS MINE SPOIL SUBSTRATUM AMENDED WITH TREATED SEWAGE SLUDGE

摘要

Ecologic restoration criteria in degraded areas from extraction activities require to make use of their own wastes. These materials do not meet fertility conditions to guarantee the restoration success and therefore need the incorporation of organic amendments to obtain efficient substratum. It is propose to reduce the deficiencies in the organic material and restoration material nutrients with the contribution of treated sewage sludge. To study the mobility of polluting agents through the substratum, the authors have designed an experiment that attempts to reproduce the behavior of Cd in the soil as a part of the non-saturated zone. This work was based on a controlled experiment using soil columns. The water contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system, to cover the surface and then percolate through the soil. The collection of leached water took place 24 hours after the latest application. A calcareous substratum was amended with 30,000, 90,000 and 180,000 kg sludge/ha. Cadmium was analyzed in soil samples at intervals of 15 cm of depth, also leachates were collected at the bottom of the columns and Cd were also analyzed. No important displacement or mobility of Cd has been found in the calcareous soil examined in this study. Significant quantities of heavy metals did not appear in leachates, which means that the pollutants analyzed in this research, and under these irrigation conditions, are not likely to be a source of contamination of waters.