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The Iguape-Cananéia estuary-lagoon complex (CELIC) has different environment conditions between the northern and Southern sections, with different anthropic pressures. Current study evaluates the space and time variation of bioavailability of metals Fe, Zn, Mn, Co, Cu, Cr, Cd, Pb and Ni in sediments at 8 sites of CELIC during two periods in 2013. Metal bio-availability was assessed by the method of simultaneous extractions of metal ions and sulfates volatized by acidification (SEM/SVA). There was a broad space and time variability in the parameters under analysis where mean availability of metals followed the sequence Fe>Mn>Zn>Pb>Cu. All sites provided ratio SEM/SVA > 1 for metal ions Pb, Cd, Ni, Cu and Zn, with greater toxicity in the northern sediments. The above suggests bio-availability of the metals and highlighted the potential of the sediments, adversely affecting local biota. Results underscore the influence of numerous urban, agricultural and mining activities on the system, mainly derived from the river Ribeira de Iguape. [ABSTRACT FROM AUTHOR]

This article describes an analytical procedure for the determination of copper in fuel samples using the modified graphite electrode basal pyrolysis (BPPGME) by tetrazolium salts: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2Htetrazolium (MTT) Br]. The determination of metals in fuel is an issue of environmental relevance because it believes that these elements can be released into the atmosphere causing damage to the environment and health. Fuel samples (ethanol, biodiesel and gasoline) were previously digested in a microwave oven using nitric acid and peroxides (biodiesel) and only nitric acid (alcohol and gasoline). The metal ion studied reacted on the surface of the chemically modified electrode to produce marked changes in the corresponding voltammograms. In order to determine the species of interest the best results were at pH 5.0 for copper and pH 6.0 for other species. The concentration scale for copper was 2.0x10-6 at 1.25 X 10-5 mol L-1. The limit of detection in fuels of samples (ethanol, biodiesel or gasoline), by ARV was 2.5x10-6 mol L-1. The accuracy of the proposed technique was compared by providing similar results, ie the copper concentration in the samples analyzed by both techniques at a non-statistically different 95% certainty level. [ABSTRACT FROM AUTHOR]