Adsorption Of Cadmium And Copper In Representative Soils Of Eastern Amazonia, Brazil

Studies of heavy metals adsorption in soil play a key role in predicting environmental susceptibility to contamination by toxic elements. The objective of this study was to evaluate cadmium (Cd) and copper (Cu) adsorption in surface and subsurface soil. Samples of six soils: Xanthic Hapludox (XH1 and XH2), Typic Hapludox (TH), Typic Rhodudalf (TR), Typic Fluvaquent (TF), and Amazonian dark earths (ADE) from Eastern Amazonian, Brazil. The soils were selected for chemical, physical and mineralogical characterization and to determine the adsorption by Langmuir and Freundlich isotherms. All soils characterized as kaolinitic, and among them, XH1 and XH2 showed the lowest fertility. The Langmuir and Freundlich isotherms revealed a higher Cu (H curve) than Cd (L curve) adsorption. Parameters of Langmuir and Freundlich isotherms indicate that soils TR, TF and ADE has the greatest capacity and affinity for metal adsorption. Correlation between the curve adsorption parameters and the soil attributes indicates that the pH, CEC, OM and MnO variables had the best influence on metal retention. The Langmuir and Freundlich isotherms satisfactorily described Cu and Cd soil adsorption, where TR, TF and ADE has a lower vulnerability to metal input to the environment. Besides the pH, CEC and OM the MnO had a significant effect on Cu and Cd adsorption in Amazon soils.3753005301

Simulação da movimentação de agrotóxicos no solo com o uso de geotecnologias, como instrumento para avaliação do potencial de risco de contaminação de águas subterrâneas na Amazônia Oriental.

Pesticides use represents a great environmental risk with high economic cost. The objective of this study is to investigate groundwater contamination risk in a small watershed in northeastern Pará State, Brazil, coupling remote sensing, GIS techniques, and simulations. We have confirmed a high risk exposure to contamination by Dimethoate in 67.76 ha, which represents 1.67% of the total watershed area. According to these analyses, Dimethoate has the potential to reach 12.96 m depth in the soil. The groundwater in the study area has a high risk of exposure to contamination by this pesticide, as the water table depth ranges from 1.5 to 13.0 meters. The shallow water table together with soil and geological characteristics increases the potential risk of contamination of groundwater

Watershed studies in a region mainly occupied by small holder farms in the eastern Amazon.

Abstract ID: 71

An upper limit to the photon fraction in cosmic rays above 10**19-eV from the Pierre Auger Observatory

An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies above 10{sup 19} eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favored