Banca de DEFESA: WENDEL VALTER DA SILVEIRA PEREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : WENDEL VALTER DA SILVEIRA PEREIRA
DATE: 24/02/2023
TIME: 10:00
LOCAL: meet.google.com/mtp-drns-etw
TITLE:

"Contamination by rare earth elements in gold mining areas in the eastern Amazon"

KEY WORDS:

Serra Pelada; Cachoeira do Piriá; emerging pollutants; pollution indices; ecological risks; lanthanides.

PAGES: 71
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

Gold (Au) is exploited by rudimentary methods in several artisanal mines in the Amazon, which generates residues that can harm the ecosystem and public health with pollution by rare earth elements (REEs). The objectives of this study were to determine the concentrations and risks of REEs in areas altered by artisanal Au mining in the southeastern and northeastern Amazon. The areas studied in the southeastern region referred to the zone of influence of the Serra Pelada artisanal mine, located in the municipality of Curionópolis, state of Pará, and included agricultural, urban, mining, and native forest areas. In the northeastern Amazon, the studied areas corresponded to artisanal Au mines in Cachoeira do Piriá, state of Pará, where miners use methods such as underground exploration, reprocessing by cyanidation, and surface colluvial mining. The collected samples were submitted to chemical and granulometric characterization. The concentrations of REEs were quantified by inductively coupled plasma mass spectrometry and used to estimate levels of pollution and risks to the environment and human health. In general, the properties showed marked differences between areas without significant anthropic impact and altered areas, which had lower levels of organic matter and less acidity. Most REEs had higher concentrations in anthropized areas when compared to reference areas. The most alarming contamination factors were observed for lanthanum (La) and yttrium (Y) in agricultural areas in Serra Pelada, and for cerium (Ce), europium (Eu), La, neodymium (Nd), praseodymium (Pr), samarium (Sm), and scandium (Sc) in the underground and cyanidation mining areas in Cachoeira do Piriá. The highest enrichment factors were observed for Y in Serra Pelada, ranging from 18.2 to 44.4, and for Ce, La, Nd, Pr, and Sc in Cachoeira do Piriá, ranging from 5.5 to 20. Ecological risks from individual exposure to REEs were low in all studied areas, but simultaneous exposure was associated with risks ranging from moderate (167.3) to high (365.7) in Cachoeira do Piriá. On the other hand, risks to the health of adults and children were not evidenced. The results of this study indicate that mitigation measures must be implemented to protect the environment from the impacts of REEs, considering the levels of pollution, enrichment, and ecological risks of these emerging pollutants in areas altered by human activities in the eastern Amazon.

BANKING MEMBERS:
Externo à Instituição - PAULA GODINHO RIBEIRO - ITV
Presidente - 6388356 - ANTONIO RODRIGUES FERNANDES
Externa à Instituição - CYNTHIA DE OLIVEIRA - UFLA
Externa à Instituição - FRANCIELLE ROBERTA DIAS DE LIMA - UFLA
Externo à Instituição - GABRIEL CAIXETA MARTINS - ITV