Qualidade do Solo em lixão Desativado no Município de Brejinho, RN

Abstract

The generation of solid waste is inevitable. In all anthropic activities, the generation of undesirable by-products occurs. However, the destination of these by-products should meet the technical criteria and the capability to support of the environment. The irregular disposition of these waste results in environmental degradation processes that must be remedied in order to establish a new balance in the environment. The purpose of this paper is to identify the environmental degradation processes that occur in the area by evaluating the physical and chemical attributes and the levels of heavy metals in the soil, thus that can serve as a basis for the planning and monitoring of the recovery of the degraded area. Therefore, soil samples were collected in an area of irregular solid waste disposal in the city of Brejinho-RN, and evaluated the following attributes: bulk density, particle density, particle-size distribution, total soil porosity, pH, electrical conductivity, K+, Na+, Ca2+, Mg2+ exchangeable, potential acidity, available phosphorus, total cation exchange capacity, base saturation, organic C, organic matter and total nitrogen. In addition, the concentrations of heavy metals in their total fractions of Cu, Pb, Zn, Cr, Mn and Ba. With the evaluation of these attributes, the soil under native forest and the soil of the dump were compared, it was verified that the use of the soil for the disposal of residues caused changes in the physical, chemical and total contents of heavy metals. Therefore, it is possible to conclude that there was loss of soil quality with the irregular disposal of solid residues. The alkalinization of the soil is the process of degradation active in the area of the dump that must be corrected in order to achieve the phytostabilization. The dump’s soil presented contamination by Zn, revealing itself as a class 2 soil, according to the current legislation. The combination between sandy texture and soil enrichment with phosphorus and nitrogen extends the soil-source condition, which requires the application of environmental control measures.