title: Soil contamination assessment for Pb, Zn and Cd in a slag disposal area using the integration of geochemical and microbiological data.
abstract: Improper disposal of mining waste is still considered a global problem, and further details on the contamination by potentially toxic metals are required for a proper assessment. In this context, it is important to have a combined view of the chemical and biological changes in the mining dump area. Thus, the objective of this study was to evaluate the Pb, Zn and Cd contamination in a slag disposal area using the integration of geochemical and microbiological data. Analyses of soil organic matter (SOM), pH, Eh, pseudo-total concentration of metals, sequential extraction and microbial community by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were conducted. Metal availability was evaluated based on the geoaccumulation index (Igeo), ecological risk ([Formula: see text]), Risk Assessment Code (RAC) and experimental data, and different reference values were tested to assist in the interpretation of the indices. The soil pH was slightly acidic to neutral, the Eh values indicated oxidized conditions and the average SOM content varied from 12.10 to 53.60 g kg-1. The average pseudo-total concentrations of metals were in the order of Zn > Pb > Cd. Pb and Zn were mainly bound to the residual fraction and Fe-Mn oxides, and a significant proportion of Cd was bound to the exchangeable and carbonate fractions. The topsoil (0-20 cm) is highly contaminated (Igeo) with Cd and has a very high potential ecological risk ([Formula: see text]). Higher bacterial diversity was mainly associated with higher metal concentrations. It is concluded that the integration of geochemical and microbiological data can provide an appropriate evaluation of mining waste-contaminated areas.
authors.affiliation: Department of Geotechnical Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil.
authors.forename: Mariana Consiglio
authors.initials: MC
authors.lastname: Kasemodel
authors.affiliation: Department of Geotechnical Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil.
authors.forename: Jacqueline Zanin
authors.initials: JZ
authors.lastname: Lima
authors.affiliation: Department of Hydraulics and Sanitary Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil.
authors.forename: Isabel Kimiko
authors.initials: IK
authors.lastname: Sakamoto
authors.affiliation: Department of Hydraulics and Sanitary Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil.
authors.forename: Maria Bernadete Amancio
authors.initials: MB
authors.lastname: Varesche
authors.affiliation: Department of Hydraulics and Sanitary Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil.
authors.forename: Julio Cesar
authors.initials: JC
authors.lastname: Trofino
authors.affiliation: Department of Geotechnical Engineering, University of São Paulo, 400 Trabalhador São Carlense Ave., São Carlos, 13566-590, Brazil. valguima@sc.usp.br.
authors.forename: Valéria Guimarães Silvestre
authors.initials: VG
authors.lastname: Rodrigues
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D004787:Environmental Pollution / Q000032:analysis; D007854:Lead / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D008906:Mining; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D015032:Zinc / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D007854:Lead; D015032:Zinc
keywords: Geoaccumulation index; Microbial diversity; Mining area; PCR–DGGE; Potential ecological risk; Sequential extraction