Page 27 - PR 2014 2016 07 Nuclear Science and Technology

Nuclear Science and Technology | Progress Report 169

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an area of 8,511 km ). Vehicle emissions are one emerged plants, with floating or submerged
of the main contributions to atmospheric parti- leaves and submerged or free floating plants.
cle concentrations, including their exhaust, the Macrophytes are used for monitoring aquatic
mechanical wear of tires and brakes and the environments by changes in the composition
ejection of particles from the pavement by re- of the communities as impact indicators and
suspension processes. Several studies of metal by chemical essays to evaluate contaminant
flows in the anthroposphere point to the traffic bioaccumulation. Nowadays, there is not
sector as a major contributor of diffuse metal sufficient information about trace elements
emissions. Tunnel dusts have been the subject contamination in sediments, water and mac-
of several environmental studies worldwide, rophytes in the Guarapiranga reservoir. The
since measurements inside traffic tunnels can present study aims to assess the contamina-
provide an evaluation of emission factors of tion of metallic elements in water, sediment
vehicles in real conditions. In this study, the re- and macrophytes in the Guarapiranga reser-
sults of metals and metalloids concentrations voir, to provide a more current diagnosis of this
of tunnel dusts of the Jânio Quadros tunnel, important and strategic environment.
in São Paulo city, were determined by Neu-
tron Activation Analysis. The results showed Sediment and macrophytes sampling was
higher concentration levels of Ba, Cr, Fe, Sb e made with the support of the Environmen-
Zn in relation to similar studies, mainly in the tal Agency of the state of São Paulo (CETESB),
finer fractions (<63μm). Principal component following the CETESB guidelines of sampling
analysis (PCA) indicate that the elements As, and sample preparation. The samples were
Ba, Co, Sb e Zn are originated from vehicular analyzed by Instrumental Neutron Activation
sources. (Financial support: CAPES, CNPq). Analysis (INAA), ICP OES e CV AAS in order to
determine the following elements: As, Cd, Cr,
Bioaccumulation of potentially toxic Cu, Hg, Ni, Pb and Zn. The results obtained
elements in floating aquatic macrophytes for the sediments were compared to the limit
of Guarapiranga reservoir, São Paulo values reported by The Canandian Council of
Ministers of the Environment. These values,
The Guarapiranga reservoir is one of the main TEL (Threshold Effect Level) and PEL (Probable
water supply reservoirs in the São Paulo Metro- Effect Level) indicate the concentrations limits
politan Region, providing water for about 4 mil- which can cause adverse effects to the biota.
lion inhabitants. The contamination of aquatic The Cu levels exceeded TEL values in all sites.
ecosystems by trace elements originating from It should be noticed that Cu is frequently used
anthropogenic activities is of great concern. as algaecide in the reservoir, as CuSO .
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Besides the increase of metallic elements, the
eutrophication of aquatic systems is a serious The results obtained for the macrophytes
problem, since it can affect aquatic community were compared to reference values for aquatic
dynamics. In Brazil, domestic sewage is the plants, and most of the analyzed elements
main input of nutrients, which in turn aggra- presented concentration levels above reference
vates the process of eutrophication. This results values. There was no statistical difference of
in excessive growth of aquatic macrophytes. the analyzed metals among the studied species
Macrophytes are defined as macroscopic size of macrophytes: Eichhornia crassipes (Mart.)
higher plants, which are present in aquatic Solms. (Aguapé), Pistia stratiotes L. (Alface
environments. They are classified as rooted and d’água), Salvinia herzogii de la Sota (Salvínia,