Page 178 - 00. Complete Version - Progress Report IPEN 2014-2016

178 Nuclear Science and Technology | Progress Report

in the inner layer (Fig 22). Results of bark anal- sampling sites in the CUASO were cleaned,
yses collected in different sampling sites of freeze-dried and ground for analyses. The an-
São Paulo Metropolitan Region indicated vari- alytical methods of X - ray fluorescence spec-
ability in the elements concentrations with trometry (XRFS) and neutron activation anal-
the proximity and intensity of the different ysis (NAA) were applied to these analyses.
emission sources and these results indicated Replicate analyses of a lichen sample by XRFS
four possible emission origins, such as vehic- and NAA, indicated good homogeneity of the
ular plus soil resuspension, industrial, marine sample for the elements determined. The li-
aerosol and tree bark composition itself. chen results showed that the mean concentra-
tions of As, Br, Ca, Cd, Co, Cr, Cs, Rb, Sb, Se and
U were higher in samples from CUASO than
those from regions considered unpolluted. For
Fe, K, La, S, V and Zn, they were of the same
order of magnitude. For some elements, the
hot spots of their concentrations were prob-
ably verified due to the dispersion of particu-
late material from laboratory or incinerator
emissions and building constructions.

Production and characterization of
biological reference materials

A certified reference material (CRM) is a ref-
erence material accompanied by a certifi-
cate, whose values are certified by a proce-
dure which establishes its traceability to an
accurate realization, in which the value is ex-
pressed and each certified value is accompa-
nied by an uncertainty at a given level of con-
fidence. Certified reference materials are still
not widely used in Brazil and other Latin Amer-
ican countries. The main reason is the high cost
of these materials, since most of them are im-
Fig 22
ported. Reference materials are important tools
in the quality assurance of analytical results
Biomonitoring of chemical element as they are used in method validation, calibra-
pollutants using Epiphytic lichen tion of instruments and in the realization of

the traceability of analytical results to stated
In this study, for passive biomonitoring of air references. The Neutron Activation Laboratory
pollution levels at the Cidade Universitária has been involved in the development of Bra-
Armando Salles de Oliveira (CUASO), Univer- zilian biological reference materials, such as
sity of São Paulo campus, epiphytic lichens of mussel and fish with support of the Interna-
Canoparmelia texana species were used. The tional Atomic Energy Agency (IAEA).
lichens collected from tree barks at different

Instituto de Pesquisas Energéticas e Nucleares