Título: | ASSESSMENT OF THE DEGRADATION OF OIL IN MANGROVE SEDIMENT: STUDY CASE, GUANABARA BAY | |||||||
Autor: |
CASSIA DE OLIVEIRA FARIAS |
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Colaborador(es): |
ANGELA DE LUCA REBELLO WAGENER - Orientador CLAUDIA HAMACHER - Coorientador |
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Catalogação: | 08/JAN/2007 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | |||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=9446&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=9446&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.9446 | |||||||
Resumo: | ||||||||
Brazil is observing an increasing growth in the petroleum
industry resulting
in an equally increased risk of accidents involving
petroleum and derivatives. A
great part of the Brazilian coastal plain is covered by
mangroves, which are an
important ecosystem for procreation and preservation of
marine and terrestrial
species. As a result it is urgent the need to study the
oil dynamics in this
environment. To do so, the Guanabara Bay was chosen, since
this area is
subjected to intense pollution by oil and its derivatives.
In the year 2000,
occurred the largest oil spill in the Bay. Around 1,800 m3
of oil, type MF380,
were spilled, reaching importat mangrove areas. In the
mangrove forests were
chosen three sites to monitor the evolution of the spilled
oil trough time. The
mangroves sites in Surui and Nova Orleans were chosen,
since they were
directly reached by the accident. The site at Piedade, was
chosen as a reference
area, since there was not evidences of contamination in
this site. In all areas it
was carried out annual sampling since the year 2,000,
adding up to five surveys.
In each mangrove site sediment samples were collected in
depth profiles in order
to analyze the aliphatic hydrocarbons, PAH, hopanes and
steranes. Besides
these parameters, the following accessory data were also
analyzed: umidity
content, organic carbon, grain size, pH and Eh. Only in
one sampling (fourth) the
acid volatile sulfides (AVS) and sulfide associated metals
were analyzed (SEM).
The extraction of organic compounds (aliphatic, PAHs,
hopanes and steranes)
was done in Soxhlet (EPA 3540C), the extract was
concentrated, fractionated in
column chromatography and analyzed bt CG-DIC (aliphatic)
CG-EM (PAHs,
hopanes and steranes) (EPA-8270D). The AVS were analyzed
by colorimetric
method and in the extract resulted from the sample
acidification were determined
the associated metals to the AVS. The Zn and Al wre read
by atomic absorption
spectrophotometry with flame detector and the other metals
(Ni, Cu, Cd and Pb)
were analyzed by atomic absorption spectrophotometry with
graphite oven. The results demonstrated that after four
years since the accident, occurred a
decrease of approximately 70% of the initial concentration
of aliphatic
hydrocarbons and PAH in the impacted mangroves. Even
though the observed
decrease, it is still detected the presence of HPAs in
high levels of concentration
in Surui Site (28 ug g-1). In Piedade Site however, it was
not observed variations
in the concentration of PAHs in the samplings, showing
approximate values of
600 ng g-1. The kinetic degradation of the PAHs presented
higher values in the
lower molecular weight compounds and with lower
alquilation grades. The
hopanes and steranes data attested the existence of the
spilled oil in the Surui
and Nova Orleans mangroves, however in Piedade, the
presence of oil was not
detected. Based in the interpretation of the mass spectra
and comparison with
literature data it was possible to suggest the presence of
diagenetic PAHs from
different tetra and penta cyclic compounds. Also the
distribution of higher
molecular weight n-alkanes in the sediments highlighted
the presence of plant
products. The results obtained for the relation SEM/AVS
shows that the deeper
samples in Piedade and Nova Orleans sites and in the
superficial samples at
Surui site, present values higher than 1, indicating the
occurrence of bioavailable
metals. The metal content values for Guanabara Bay was
expected to be higher.
However, as the analyzed sites are located near the
Guapimirim Preservation
Area, these mangroves are not directly subjected to the
industrial region.
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