Anthropogenic and natural inputs of polycyclic aromatic hydrocarbons in the sediment of three coastal systems of the Brazilian Amazon.

Polycyclic aromatic hydrocarbons (PAHs) were measured in 32 surface sediment samples collected around three cities (Barcarena, Belém, and Santana) located on the coast of the Brazilian Amazon. The concentration of total PAHs ranged from lower than detection limit to 33,101 ng g-1 in a sample from Barcarena and was related to a large aluminum industrial complex and port activities. In Belém, which is the most populated area in the Amazon region, PAHs were probably derived from untreated sewage discharge and inputs from a large municipal landfill. Pyrogenic PAHs were predominant in both cities, with a smaller contribution of petrogenic PAHs. Low alkylated PAH levels may be associated with small boats and ship traffic. Santana had low total PAH concentrations, with a predominance of unusual alkylated PAHs, probably related to diagenetic transformations of organic matter in the sediment. In general, PAH concentrations in the samples were low and may reflect baseline levels for this Amazon estuarine system.

Sugars--dominant water-soluble organic compounds in soils and characterization as tracers in atmospheric particulate matter.

The presence of saccharides is being reported for aerosols taken in urban, rural, and marine locales. The commonly found primary saccharides are alpha- and beta-glucose, alpha- and beta-fructose, sucrose, and mycose with lesser amounts of other monosaccharides. Saccharide polyols are also found in some airsheds and consist mainly of sorbitol, xylitol, mannitol, erythritol, and glycerol. In temperate climate areas these compounds increase from negligible concentrations in winter aerosols (usually dominated by levoglucosan and related anhydrosaccharides from biomass burning) to a maximum in late spring-summer, followed by a decrease to winter. The composition of the saccharide mixtures suggests soil and associated microbiota as the source. Saccharide analyses of soils confirmed these compositions. Therefore, we propose resuspension of soil (also unpaved road dust) from agricultural activities as a major component of aerosol particles and the saccharides are the source specific tracers. In addition, the saccharides as well as the anhydrosaccharide derivatives from biomass burning are completely water soluble and thus contribute significantly to the total water-soluble mass of aerosols.

Three series of high molecular weight alkanoates found in Amazonian plants.

Electron impact mass spectra were measured by high temperature high resolution gas chromatography-mass spectrometry (HT-HRGC-MS) for three homologous series of high molecular weight compounds present in the Amazonian plants Marupá (Simaruba amara) and Brazil nut (Bertholettia excelsa). Based on their mass spectra, the compounds were identified as three wax ester series of alpha-tocopherol (vitamin E), beta-tocopherol and phytol (2,6,10,14-tetramethylhexadec-14-en-16-ol). The interpretations are supported by high resolution mass spectrometry and GC retention indices of authentic standards.