Banca de DEFESA: WENDEL VALTER DA SILVEIRA PEREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : WENDEL VALTER DA SILVEIRA PEREIRA
DATA : 20/02/2020
HORA: 08:30
LOCAL: Auditório PgAgro
TÍTULO:

CHEMICAL FRACTIONATION AND BIOACCESSIBILITY OF POTENTIALLY TOXIC ELEMENTS IN AREA OF ARTISANAL GOLD MINING IN THE AMAZON

PALAVRAS-CHAVES:

Heavy metals, health risk, availability, environmental risk

PÁGINAS: 54
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Química do Solo
RESUMO:

The Serra Pelada mine was discovered in the early 1980s, attracting workers from around the world to explore thousands of gold tons until 1990, when the Brazilian government closed the mining activities. Currently, piles of mining wastes are deposited unprotected on the soil surface of the area, which can put the population's health at risk. Some studies have been carried out to characterize environmental contamination by potentially toxic elements (PTEs) in the region, but no approaches have been made on the mobility, bioavailability and bioaccessibility of these elements. Chemical fractionation and oral and pulmonary bioaccessibility of barium (Ba), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) were studied in soils and artisanal gold mining residues of Serra Pelada, Pará, Brazil. 10 samples of mining waste, 10 in urban areas, 5 in agricultural areas and 2 in native vegetation areas without anthropic influence were collected. Chemical, physical and mineralogical characterization of the samples was carried out. Pseudototal concentrations were extracted with acid digestion in a microwave oven. Chemical fractionation was obtained by the BCR (Bureau Community of Reference) sequential extraction method, oral bioaccessibility in the gastric and intestinal phases was obtained by the SBET (Simple Bioaccessibility Extraction Test) method, while pulmonary bioaccessibility was obtained through the Gamble solution. The concentrations were quantified by flame atomic absorption spectroscopy and subjected to descriptive statistical analysis. The results indicated contamination by Ba, Cu and Ni, especially for Ba in the mining area. Chemical fractionation revealed that the elements predominated in the residual form, however high concentrations of Ba are in high reactivity forms. The Ba bioaccessible concentrations via oral, in both phases, were higher in areas with a greater anthropic influence degree. Cr and Cu were more bioaccessible in the intestinal phase and Zn in the gastric phase, regardless of the area. Pulmonary bioaccessible concentrations were not found for Ba, Cr and Zn, while Cu, Ni and, mainly, Pb, were bioaccessible via inhalation. The EPTs studied deserve attention for their high total concentrations (which indicate high potential risk), concentrations in the high mobility fractions and bioaccessible concentrations (oral and pulmonary) found in Serra Pelada, mainly in the areas of greatest anthropogenic occupation, where the elements are in direct contact with the local population.

MEMBROS DA BANCA:
Presidente - 6388356 - ANTONIO RODRIGUES FERNANDES
Interno - 030.493.086-56 - SILVIO JUNIO RAMOS - ITV
Externo à Instituição - EDNA SANTOS DE SOUZA - UNIFESSPA
Externo à Instituição - CRISTINE BASTOS DO AMARANTE - MPEG