title: Biological attributes of rehabilitated soils contaminated with heavy metals.
abstract: This study aimed to evaluate the effects of two rehabilitation systems in sites contaminated by Zn, Cu, Pb, and Cd on biological soil attributes [microbial biomass carbon (Cmic), basal and induced respiration, enzymatic activities, microorganism plate count, and bacterial and fungal community diversity and structure by denaturing gradient gel electrophoresis (DGGE)]. These systems (S1 and S2) consisted of excavation (trenching) and replacement of contaminated soil by uncontaminated soil in rows with Eucalyptus camaldulensis planting (S1-R and S2-R), free of understory vegetation (S1-BR), or completely covered by Brachiaria decumbens (S2-BR) in between rows. A contaminated, non-rehabilitated (NR) site and two contamination-free sites [Cerrado (C) and pasture (P)] were used as controls. Cmic, densities of bacteria and actinobacteria, and enzymatic activities (β-glucosidase, acid phosphatase, and urease) were significantly higher in the rehabilitated sites of system 2 (S2-R and S2-BR). However, even under high heavy metal contents (S1-R), the rehabilitation with eucalyptus was also effective. DGGE analysis revealed similarity in the diversity and structure of bacteria and fungi communities between rehabilitated sites and C site (uncontaminated). Principal component analysis showed clustering of rehabilitated sites (S2-R and S2-BR) with contamination-free sites, and S1-R was intermediate between the most and least contaminated sites, demonstrating that the soil replacement and revegetation improved the biological condition of the soil. The attributes that most explained these clustering were bacterial density, acid phosphatase, β-glucosidase, fungal and actinobacterial densities, Cmic, and induced respiration.
authors.affiliation: Agricultural Microbiology Postgraduate Program, Department of Biology, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil.
authors.forename: Jessé
authors.initials: J
authors.lastname: Valentim dos Santos
authors.affiliation: Agricultural Microbiology Postgraduate Program, Department of Biology, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil.
authors.forename: Maryeimy
authors.initials: M
authors.lastname: Varón-López
authors.affiliation: Department of Soil Science-Sector of Biology, Microbiology and Biological Processes Laboratory, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil.|Sector of Biology, Soil Microbiology Laboratory, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Postal Box 476, Florianópolis, SC, 88040-900, Brazil.
authors.forename: Cláudio Roberto
authors.initials: CR
authors.lastname: Fonsêca Sousa Soares
authors.affiliation: Department of Soil Science-Sector of Biology, Microbiology and Biological Processes Laboratory, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Lopes Leal
authors.affiliation: Department of Soil Science-Sector of Biology, Microbiology and Biological Processes Laboratory, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil.|Vale Technological Institute, Rua Boaventura da Silva, 955, Nazaré, Belem, PA, 60055-090, Brazil.
authors.forename: José Oswaldo
authors.initials: JO
authors.lastname: Siqueira
authors.affiliation: Department of Soil Science-Sector of Biology, Microbiology and Biological Processes Laboratory, Federal University of Lavras, Postal Box 3037, CEP 37200-000, Lavras, MG, Brazil. fmoreira@dcs.ufla.br.
authors.forename: Fatima Maria
authors.initials: FM
authors.lastname: de Souza Moreira
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D035201:Brachiaria / Q000254:growth & development*; D001938:Brazil; D005052:Eucalyptus / Q000254:growth & development*; D019216:Metals, Heavy / Q000032:analysis*; D059013:Microbial Consortia; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D014510:Urease / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D014510:Urease
keywords: Denaturing gradient gel electrophoresis (DGGE); Enzymatic activities; Microbial biomass; Microorganism plate count; Phytoremediation; Soil microbial respiration; Trace elements