Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: Mitiko Saiki x
  • All content x
Clear All Modify Search

Abstract  

The determinations of trace elements in tissues of herons are of great interest in order to evaluate environmental contamination. As the herons are at the top of the food chain they tend to accumulate high concentrations of contaminants in their tissues. Besides, the effects of pollution are also severe for this species, endangering the survival and reproduction of bird populations. In the present study, concentrations of the trace elements Br, Co, Cs, Fe, Rb, Se, and Zn were determined in livers from Great Egret (Ardea alba) species. The liver samples were those obtained from the adult specimens found dead in the metropolitan region of São Paulo, SP, Brazil. The liver samples were ground, freeze-dried and the elements were determined by the method of neutron activation analysis. The elemental concentration obtained in livers of these species showed wide variations depending on the element. Comparisons made between our results with literature data indicated that element concentrations obtained for herons from metropolitan region of São Paulo are higher or at the same order of magnitude of those obtained for specimens from polluted areas. Comparisons made between the results obtained for different genders of herons by applying nonparametric Mann–Whitney U test at the significance level of 0.05 indicated that female herons present Co and Se concentrations lower than those from males.

Restricted access

Abstract  

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.

Restricted access