USE OF GRAVEL FROM MARITIME OIL DRILLING WELLS AS A SOIL ACIDITY CORRECTION AND SPECIES CULTURE FOR REFORESTATION AND RECOVERY OF DEGRADED AREAS
Offshore gravel. Sodium saturation. pH dynamics. Heavy metals.Over the years, the amount and variety of waste generated as a result of industrial growth has grown significantly and gravel from oil wells has been one of them, which can bring serious environmental problems due to the presence of elements with high contaminating power. in its composition. In contrast, the residue also has the presence of some essential nutrients for plants and, therefore, for its use to be possible, studies are needed to elucidate the positive and negative effects on the soil-plant system. From this, seeking to reduce costs for the environmentally adequate disposal of these residues and also due to the increase in the costs of commercial fertilizers, their use in agricultural soil can be an attractive alternative - in view of its corrective potential for soil acidity. and nutritional - both from an environmental and an economic point of view. Thus, it is necessary to adopt actions to quantify and characterize these residues, in order to define the most appropriate treatment or conditioning systems, as well as their reuse. In this scenario, the present work presents the following hypotheses:
a) Marine gravel (offshore) when subjected to desalination has the potential to be used as a fertilizer and soil acidity corrector due to its nutrient composition and its neutralizing power; b) The use of gravel for drilling oil wells without prior treatment causes the release and consequent increase in the concentration of sodium salts in the medium and heavy metals, which can lead to salinization of the system and even contamination of the soil; c) The gravel presents itself as an alternative source of correction of acidity of weathered soils, being able to potentiate the development of vegetal species used in the reforestation and recovery of degraded areas. Seeking to test these hypotheses, the work was divided into three chapters: I - Dynamics of pH and sodium saturation in weathered soils treated with residues from drilling offshore oil wells and risks of contamination by heavy metals. This section aims to study the dynamics of pH and sodium saturation (Na+) in acidic soils incubated with gravel from offshore oil drilling and to analyze the risks of contamination by heavy metals and the way they are retained in the soil. II - Development of Corn (Zea mays L.) in soils treated with gravel from offshore oil wells. The objective of this chapter was to evaluate the development of corn as a bioindicator species in soils with different textural classes with and without pH correction treatment by the use of marine oil drilling gravel. III - Use of offshore gravel as a soil acidity corrector and cultivation of plant species for reforestation and recovery of degraded areas. The objective was to analyze the development of Mulungu (Erythrina velutina Willd.) and Eucalyptus (Eucalyptus grandis W. Hill) forest species in soils with different textural classes with and without pH correction treatment by the use of offshore oil drilling gravel.