Banca de DEFESA: OSVALDO GATO NUNES NETO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : OSVALDO GATO NUNES NETO
DATA : 29/02/2024
HORA: 14:00
LOCAL: A Definir
TÍTULO:

ANIMAL MODELS AS ENVIRONMENTAL INDICATORS OF CONTAMINATION OF AMAZONIAN ENVIRONMENTS BY HEAVY AND ESSENTIAL METALS

 

 

PALAVRAS-CHAVES:

Cattle; DMA-80; ICP-MS; bioacumulation; metals; Tapajós river basin 

PÁGINAS: 114
RESUMO:

The Tapajós River basin is one of the prominent regions for mercury contamination from mining activities. It is worth noting that the element mercury is not the only heavy metal with potential harm to the health of Amazonian populations. Arsenic, cadmium and lead are toxic metals known to be present in the region, either due to anthropogenic or natural action. In addition to toxic forests, the risks of excessive consumption of even metals considered essential should be warned.  This thesis presents three chapters that deal with the monitoring of toxic and essential metals in the Lower Amazon mesoregion. In chapter I, we determine the sensitivity and specificity of Hg detection performed with DMA-80 and whether these results are reliable compared to those obtained with the inductively coupled plasma mass spectrometry (ICP-MS; VG PQ Excel, Thermo Elemental, USA), which is the gold standard. The results obtained with DMA-80 showed an overall mean Hg of 1.90 ± 0.18 μg/kg, higher (p<0.05) than the mean of those obtained by ICP-MS (1.55 ± 0.13 μg/kg). The linear regression analysis comparing the Hg levels obtained with the two devices was within the 95% prediction range, and a high correlation coefficient showed agreement between the devices. The Bland-Altman analysis showed that DMA-80 showed a positive bias of 6.5% in relation to ICP-MS, which is more evident in samples with high Hg concentrations. DMA-80 was efficient in determining whether Hg levels exceeded the maximum allowable levels required by the European Union, USA and Brazil, with specificity and sensitivity above 95%. In chapter II, we considered the evaluation of the concentration of toxic metals, such as mercury (Hg), lead (Pb), cadmium (Cd) and arsenic (As), in muscle and liver tissue samples from cattle belonging to six municipalities in the Lower Amazon region. It was found that the cattle had Hg concentrations above the maximum recommended levels (MRL) established by the Brazilian government, and 10% of the animals analyzed had concentrations above the allowed. Regarding Pb, animals with excess of this toxic metal in the muscle were found in the municipalities of Itaituba (10%) and Monte Alegre (20%). In the data on the concentrations of toxic elements in the liver of cattle, it was found that the cattle presented Hg concentrations above the maximum recommended levels (MRL), and 70% of the animals analyzed with concentrations above the allowed were identified as animals with excess Hg in the liver in all the municipalities studied. Animals with excess Pb were found in the liver in the municipalities of Itaituba (30%) and Monte Alegre (30%). In Chapter III we determine the concentrations of essential elements such as cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se) and zinc (Zn) in muscle and liver tissue of cattle consumed in municipalities of the western region of Pará. We found that cattle had concentrations of Cu, Se and Zn above the maximum recommended levels (MRL) established by the Brazilian government. The HQ results indicated that adverse effects from an intake of muscle tissue are unlikely. The total target risk quotient (TTHQ) revealed that all municipalities, except for the muscle tissue samples from Itaituba, were exposed to the risks of excessive consumption of these minerals, indicating that the degree of accumulation of essential elements in cattle in the Amazon region presents a significant risk for the consumption of the local population.

MEMBROS DA BANCA:
Presidente - 1843993 - ANTONIO HUMBERTO HAMAD MINERVINO
Interno - 1834385 - WALDINEY PIRES MORAES
Interno - 1693122 - SERGIO DE MELO
Interno - 1327077 - LUIS REGINALDO RIBEIRO RODRIGUES
Externo ao Programa - 2383549 - GUSTAVO DA SILVA CLAUDIANO - UFOPAExterna à Instituição - ADRIANA CAROPREZO MORINI - UFMS