Methods for Extracting Heavy Metals in Soils from the Southwestern Amazon, Brazil

• Published in: Water, air, and soil pollution air, and soil pollution, 2013-02, Vol.224 (2), p.1-16, Article 1430
• Main Authors: dos Santos, Sabrina Novaes, Alleoni, Luís Reynaldo Ferracciú
• Format: Article
• Language: English
• Subjects: Acids; Analysis; Animal, plant and microbial ecology; Applied ecology; Applied sciences; Atmospheric Protection/Air Quality Control/Air Pollution; Biological and medical sciences; Cadmium; Chemical contaminants; Chromium; Climate Change/Climate Change Impacts; Contaminated sediments; Discriminant analysis; Earth and Environmental Science; Environment; Environmental cleanup; Environmental monitoring; Environmental studies; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Heavy metal content; Heavy metals; Hydrogeology; Lead; Metal concentrations; Metals; Methods; Microwave oven; Microwaves; Mineral reserves; Oxidation; Pollutants; Pollution; Principal components analysis; Soil and sediments pollution; Soil contamination; Soil pollution; Soil Science & Conservation; Soil sciences; Soils; Statistical analysis; Studies; Topography; Vegetation; Water Quality/Water Pollution
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-012-1430-z

Heavy metals occur naturally in soil, at concentrations that depend on the parent material from which the soil was formed, the processes of formation, and the composition and the proportion of the components of its solid phase. Quantifying these concentrations is important for environmental studies of soil contamination and pollution, and choosing the methods for doing so is a key step in establishing heavy metal contents in soil samples. We evaluated two digestion methods (aqua regia and EPA 3051, both microwave oven-assisted) for assessing pseudo-total concentrations of Cd, Co, Cr, Cu, Ni, Pb and Zn in the surface layer (0–20 cm) of soil samples from the Brazilian agricultural frontier in the southwestern Amazon. Nineteen composite samples of the most representative soil classes for the states of Mato Grosso and Rondônia were collected under native vegetation undisturbed by human intervention. Canonical discriminant analysis and principal component analysis were used for multivariate exploration of the data. Aqua regia extracted higher amounts of Co, Ni, Pb, and Zn than EPA 3051, while levels of Cr and Cu did not differ between methods. In general, aqua regia recovered more of the metals when compared to reference soil samples.