This survey determined the physical and chemical properties of the gravel place where urban sludge from Rio Descoberto's Water Treatment Plant is disposed. Physical, chemical and biological analysis of the soil samples (n=54), sludge samples (n=2), chemical coagulant (n=20) and samples from superficial waters (n=9) and water table (n=60) were performed. As results we can emphasize the horizontal distribution of mineral phases like gibbsite, organic material, exchanged Ca, available Mn and P on the soils are originated from the sludge. Some of these mobile elements could stimulate the growing of the vegetation, but they also could contaminate the water table.
sludge from water treatment plant; degraded areas; environmental geochemistry
