Avaliação de solventes de extração por ultrassom usando-se cromatografia líquida de alta eficiência para a determinação de hidrocarbonetos policíclicos aromáticos em solos contaminados

A method using ultrasonication extraction for the determination of 17 polycyclic aromatic hydrocarbons (PAHs), selected by the USEPA and NIOSH as "consent decree" priority pollutants, in soil by High Performance Liquid Chromatography (HPLC) was studied. Separation and detection were completed in 20 min with a C18 columm, acetonitrile-water gradient elution and ultraviolet absorption and fluorescence detections. The detection limits, for a 10 µL of solution injection, were less than 9,917 ng/g in UV detection and less than 1,866 ng/g in fluorescence detection. Several organic solvents were tested for extraction of the 17 PAHs from soils. Acetone was the best solvent among the three solvents tested, and the order of the extraction efficiencies was: acetone>methanol>acetonitrile. Ultrasonication using acetone as solvent extraction was used to evaluate the biodegradation of those compounds in contaminated soil during a vermicomposting process.

Estudo comparativo de métodos para a determinação da concentração de carbono em solos com altos teores de Fe (Latossolos)

Soil organic matter (SOM) plays an important role in physical, chemical and biological properties of soil. Therefore, the amount of SOM is important for soil management for sustainable agriculture. The objective of this work was to evaluate the amount of SOM in oxisols by different methods and compare them, using principal component analysis, regarding their limitations. The methods used in this work were Walkley-Black, elemental analysis, total organic carbon (TOC) and thermogravimetry. According to our results, TOC and elemental analysis were the most satisfactory methods for carbon quantification, due to their better accuracy and reproducibility.

Urban upgrading interventions and engaging residents in fuzzy management: Case studies from Novos Alagados, Salvador, Brazil

International theory and practice have promoted state-assisted upgrading of `informal` urban areas worldwide since the late 1970s, with various forms of monitoring and assessment of impact. Two independent studies of how residents perceive and evaluate such interventions have recently been undertaken for neighbouring parts of the upgraded area of Novos Alagados on the Itapagipe peninsula in the northwestern part of Salvador, Brazil`s third largest city. These studies start from different premises and have been implemented in very different ways, but both have the objective of permitting the `voice` of the residents to be heard concerning the upgrading process. Comparing them helps highlight the essential `fuzzy` nature of values concerning urban interventions of this nature and leaves us with thought-provoking questions concerning the role of local society in relation to the state in urban development, and the potential this has for on-going forms of urban management in cities which are emerging globally. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.