Authors:Tassiane Matsubara, Mitiko Saiki, and Guilherme Zahn
In recent years, environmental concerns regarding antimony have grown considerably due to anthropogenic processes that have
resulted in increasing concentration of Sb in the environment, and also because of its impacts and possible adverse effects
to living organisms. Several techniques have been used, to obtain reliable results for Sb, since Sb is present at low level
concentration, requiring analytical instrumentation with low detection limits. The neutron activation analysis (NAA) technique
has a high metrological level for the determination of several elements in different matrices. However, Sb determination in
environmental and biological samples presents some analytical difficulties due to its low concentrations and gamma ray spectrum
interferences. The objective of this research was to study on Sb determination in environmental reference materials by NAA.
Ten environmental reference materials were selected and analyzed using long period irradiation at IEA-R1 research nuclear
reactor. The induced gamma activities of 122Sb and 124Sb were measured. Relative errors of the results demonstrated that the accuracy depends mainly on Sb radioisotope measured,
the decay time for counting and the sample composition.
Authors:Guilherme Guimarães, Guilherme Zahn, Robson Franklin, Paulo Silva, and Déborah Fávaro
The Guarapiranga Reservoir is a very important aquatic system due to the fact that it is one of the main water reservoirs
for South America’s largest city, São Paulo, Brazil. Guarapiranga basin is located within the Metropolitan Region of São Paulo
and the reservoir itself is located in the Northern part of the basin occupying approximately 26 km2. This reservoir is characterized by environmental impacts from urban invasion, industrial and sewage wastes, all of which
seriously affect its water quality and, consequently, the sediment quality. Two collection campaigns were undertaken: April
2009 and June 2010. The samples were analyzed by instrumental neutron activation analysis (INAA) in order to determine the
following elements: major (Fe, K and Na), trace (As, Ba, Br, Co, Cr, Cs, Hf, Rb, Sb, Sc, Ta, Tb, Th, U and Zn) and rare earths
(Ce, Eu, La, Lu, Nd, Sm, Tb and Yb). The organic matter and granulometric distribution were also evaluated and multivariate
analysis was applied to the results. The study of elemental ratios indicated that the amount of elements present in the Guarapiranga
Reservoir is mainly of detrital origin.
Authors:Andreza Ribeiro, Ana Figueiredo, Regina Ticianelli, Georges Nammoura-Neto, Natália Silva, Mauricio Kakazu, and Guilherme Zahn
São Paulo is the largest city in Brazil and South America with about 20 million inhabitants in the metropolitan area, more
than nine million motor vehicles and intense industrial activity, which are responsible for increasing pollution in the region.
Nevertheless, little is known concerning metal and semi-metal content in the soils of this metropolitan region. This type
of information could be extremely useful as a fingerprint of environmental pollution. The present study determined the elements
As, Ba, Co, Cr, Sb, and Zn concentrations in soils adjacent to avenues of highly dense traffic in São Paulo city to assess
their levels and possible sources. The analytical technique employed was Instrumental neutron activation analysis. The results
showed, except for Co, concentration levels higher than the reference values for soils of São Paulo, according to the Environmental
Protection Agency of the State of São Paulo guidelines. When compared to similar studies in other cities around the world,
São Paulo soils presented higher levels, probably due to its high density traffic and industrial activity. The concentrations
obtained for As and Cr indicate anthropogenic origin. The high levels of the traffic-related elements Ba, Sb, and Zn in soils
nearby high density traffic avenues indicate they may originate from vehicular exhausts.