Banca de QUALIFICAÇÃO: WENDEL VALTER DA SILVEIRA PEREIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : WENDEL VALTER DA SILVEIRA PEREIRA
DATA : 14/11/2019
HORA: 09:00
LOCAL: Auditório PgAgro
TÍTULO:

Geochemical fractionation and bioaccessibility of potentially toxic elements in an artisanal gold mining area in the Amazon

PALAVRAS-CHAVES:

Heavy metals, health risk, availability, environmental risk

PÁGINAS: 40
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Ciência do Solo
ESPECIALIDADE: Química do Solo
RESUMO:

Artisanal gold mining has been practiced in the Amazon since the 1950s. Regardless of its contribution to the local economy, this activity causes damage to ecosystems and human health, mainly due to contamination with potentially toxic elements (PTEs). In the Serra Pelada artisanal gold mine, eastern Amazon, mining caused contamination of the mine's influence area by a series of PTEs for several years, but studies on the mobility, bioavailability and bioaccessibility of these elements are scarce. The objective was to know the chemical forms (bioavailable and potentially mobile) of barium (Ba), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) through geochemical fractionation and bioaccessibility in areas under influence of the Serra Pelada gold mine, Pará, Amazon. The collections were carried out in areas of mining tailings deposit (10), residences (10), agriculture (5) and forest (2), totaling 27 samples. Geochemical fractionation was obtained by the BCR sequential extraction protocol, while oral bioaccessibility in the gastric and intestinal phases was determined by the Simple Bioaccessibility Extraction Test (SBET). The results were quantified by flame atomic absorption spectroscopy and submitted to descriptive statistical analysis. All the metals predominated in the residual form. Ba demonstrated high concentrations in the fractions of greater mobility (exchangeable + reducible + oxidizable), corresponding to 1379.58, 396.80, 358.32 and 166.37 mg kg^-1 in mining, residential, agricultural and forestry areas, respectively. Considering the most reactive fractions, the elements follow the order Ba > Cu > Ni > Cr > Pb > Zn. Ba also had the highest oral bioaccessibility, with bioaccessible concentrations in the gastric phase of 489.47 mg kg^-1 (agricultural area) and 397.58 mg kg^-1 in the intestinal phase (residential area). In the gastric phase, the order Ba > Pb > Ni > Zn > Cr > Cu was found, while in the intestinal phase the elements followed the sequence Ba > Ni > Cu > Cr > Pb > Zn. There is a high current risk to human health and the environment of Ba in the Serra Pelada mining area, with high concentrations in more mobile forms and high bioaccessibility. Cr, Cu, Pb, Ni and Zn show low current risk, but deserve attention because of the high concentrations that can be mobilized for more mobile forms under Amazonian environmental conditions and due to anthropogenic activities. These results provide important information for decision-making by environmental agencies regarding the control and remediation of contaminated soils in Serra Pelada.

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 - INT