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  • Author or Editor: S. Damatto x
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Abstract  

Since the early days of mankind, plants have been used as food and for medicinal purposes. Still, little information exists in literature about the activity concentration of 238U and 232Th decay products, as well as stable element concentrations in Brazilian plants. Activity concentrations of 226Ra, 228Ra and 210Pb, and chemical concentrations of As, Ba, Br, Cs, Co, Cr, Cu, Eu, Fe, Hf, La, Lu, Rb, Sb, Sc, Sm, Ta, Tb, Yb, Zn and Zr were determined in ten samples commonly used in Brazilian medicinal plants.

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Abstract  

The Rio Grande reservoir lies southeast of the Metropolitan Area of São Paulo. In order to evaluate if the sediments contain a historical registration of anthropogenic activity, four sediment cores were sampled from the reservoir. In these cores the Hg concentration was determined by the CV AAS technique, major and trace elements by instrumental neutron activation analysis and the sedimentation rates by the 210Pb method. The results obtained for Hg are much higher than expected, showing an anthropogenic contribution. As a general trend, the elemental concentration decreases with depth, indicating recent contamination.

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Summary  

Pantanal, located in the central region of South America, is recognized as one of the world's largest freshwater wetlands. In order to verify possible changes in this environment, a study was undertaken in Nhecolândia Pantanal, Mato Grosso do Sul State, Brazil. Two sediment cores from the Salina do Meio pond (SM1 and SM2) and one core from a small flood land named Baía (B5) were collected in 2001. The elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr were determined by instrumental neutron activation analysis (INAA). Cluster and factorial analysis were applied to the chemical data. The sedimentation rate in the SM2 core was determined by 210Pb method and the mean value found was 0.61 cm . y-1. The results obtained in the present study showed that recent geochemical processes such as desorption, precipitation and dissolution can contribute for the high water alkalinity and salinity in the saline ponds.

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