Plants of the Cerrado have shown some potential for restoration and/or phytoremediation projects due to their ability to grow in and tolerate acidic soils rich in metals. The aim of this study is to evaluate the tolerance and accumulation of metals (Cd, Cu, Pb, and Zn) in five native tree species of the Brazilian Cerrado (Copaifera langsdorffii, Eugenia dysenterica, Inga laurina, Cedrela fissilis, Handroanthus impetiginosus) subjected to three experiments with contaminated soils obtained from a zinc processing industry (S1, S2, S3) and control soil (S0). The experimental design was completely randomized (factorial 5 × 4 × 3) and conducted in a greenhouse environment during a 90-day experimentation time. The plant species behavior was assessed by visual symptoms of toxicity, tolerance index (TI), translocation factor (TF), and bioaccumulation factor (BF). C. fissilis has performed as a Zn accumulator by the higher BFs obtained in the experiments, equal to 3.72, 0.88, and 0.41 for S1, S2, and S3 respectively. This species had some ability of uptake control as a defense mechanism in high stress conditions with the best behavior for phytoremediation and high tolerance to contamination. With economical and technical benefits, this study may support a preliminary analysis necessary for using native tree species in environmental projects.

INTRODUÇÃOPara um melhor uso dos recursos naturais não só é necessário identificar-se os ambientes de uma mesma região, como também desenvolver técnicas conservacionistas mais adequadas ao uso dos solos de acordo com a sua aptidão. Como esses cuidados não se limitam a uma única propriedade rural, a melhor alternativa parece ser, então, considerar a sub-bacia hidrográfica como unidade de estudo.As bacias hidrográficas são uma unidade natural por emoldurarem, num conjunto único, os fenômenos que ocorrem no seu interior (Rezende, 1986). Uma bacia hidrográfica possui um ciclo hidrológico p r ó p r i o , r e g i d o p o r f a t o r e s c l i m á t i c o s , pedológicos, geológicos, topográficos e vegetativos específicos (Resck & Gomes, 1995).Rocha (1991) mencionou que subdividir as bacias hidrográficas em sub-bacias e microbacias tem sido de grande valia em trabalhos de campo para planejamento de recuperação ambiental. DELINEAMENTO SEMI-DETALHADO DE SOLOS EMPREGANDO AEROFOTOS NÃO-CONVENCIONAIS NA SUB-BACIA PALMITAL -RIO TURVO SUJO, MG ABSTRACTIn order to characterize the soils of the sub-basin Palmital and test airphotos non-conventional were described soil profiles and extra samples, besides the obtainance of airphotos. The samples were physically, chemistry and mineralogically analysed. The soils classes are: Distrophics Red Yellow Latosols (small plateaux, summits and concave slopes), Distrophics Yellow Latosols (convexe slopes), Distrophic Latosol Cambic (on steep slopes), Eutrophic Red Yellow Podzolic + Distrophic Latosol Cambic (accumulation glacis) and Distrophics Red Yellow Latosols + Distrophic Latosol Cambic + Distrophics Yellow Latosols (dissected slopes). The most of the soils are of low natural fertility, presenting available exchanges base and CEC (cation exchange capacity) very lows, acid pH and high alluminum saturation. The X-rays diffractograms indicate a great similarity of mineralogy composition; caolinite, goethite and gibbsite are always present. The non-conventional airphotos revealed to be of excellent clearness and stereoscopic effect and had good contribution in the identification of units for half-detailed mapping soil.

A new analytical protocol was developed to provide quantitative, single-particle identification of arsenic in heterogeneous nanoscale mineral phases in soil samples, with a view to establishing its potential risk to human health. Microscopic techniques enabled quantitative, single-particle identification of As-bearing phases in twenty soil samples collected in a gold mining district with arsenic concentrations in range of 8 to 6354 mg kg. Arsenic is primarily observed in association with iron (hydr) oxides in fine intergrowth with phyllosilicates. Only small quantities of arsenopyrite and ferric arsenate (likely scorodite) particles, common in the local gold mineralization, were identified (e.g., 7 and 9 out, respectively, of app. 74,000 particles analyzed). Within the high-arsenic subgroup, the arsenic concentrations in the particle size fraction below 250μm ranges from 211 to 4304 mg kg. The bioaccessible arsenic in the same size fraction is within 0.86-22 mg kg (0.3-5.0%). Arsenic is trapped in oriented aggregates of crystalline iron (hydr)oxides nanoparticles, and this mechanism accounts for the low As bioaccessibility. The calculated As exposure from soil ingestion is less than 10% of the arsenic Benchmark Dose Lower Limit - BMDL. Therefore, the health risk associated with the ingestion of this geogenic material is considered to be low.

Este trabalho tem como objetivo comparar mapeamentos convencional e por modelagem em SIG para solos. Na modelagem em SIG, foram utilizadas imagens Shuttle Radar Topography Mission - SRTM como referência para o cálculo da declividade. Os resultados foram comparados com um mapeamento elaborado de forma convencional e avaliou-se a sua pertinência no mapeamento de solos. Os mapeamentos de declividade, elaborado a partir das imagens SRTM, e o de solos, preparado de forma convencional, foram cruzados, sendo o produto final obtido a partir de sucessivas eliminações de áreas inferiores a 2,5Km2. Foi utilizado como parâmetro de eliminação o menor perímetro de contato. A partir das alterações verificadas, a utilização das imagens SRTM, como base para o mapeamento de declividade, possibilitou um maior detalhamento das unidades de mapeamentos pedológicos, gerando um novo mapa, resultado da adição dos métodos convencional e automatizado.