Banca de DEFESA: VINÍCIUS NOGUEIRA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : VINÍCIUS NOGUEIRA DA SILVA
DATE: 23/06/2022
TIME: 14:30
LOCAL: Google Meet
TITLE:

 Distribution, ecological risk assessment and monitoring of metals in sediments from the Rio Doce Watershed/RN

KEY WORDS:

Ecological risk. Trace elements. Sediment quality. Anthropogenic enrichment.

PAGES: 74
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

The input of pollutants such as heavy metals to water bodies can pose a risk to the aquatic ecosystem. Several human activities can contribute to the input of metals and other trace elements, especially in urbanized areas. Aquatic sediments have a great capacity to retain heavy metals, that might be released into the environment due to physicochemical changes. However, metal retention and release capacity depend on the compositional and granulometric characteristics of the sediment. Thus, the objectives of this study were to: I) evaluate the ecological risk of metals in freshwater sediments and the influence of sediment composition and granulometry on the risk and distribution of metals; II) monitor temporal and spatial variations of bioavailable metals in freshwater sediments. For this, sediment samples from the lower course of the Rio Doce Watershed were used, a region located in an urban area on the coast of Northeast Brazil. As for the first objective, the granulometric fractions with higher metal contents were the fractions in which components with a high capacity to retain metals occur, such as silt and clay, organic matter, and Fe hydroxides. In addition, the sediment samples did not present ecological risk due to the presence of metals. Regarding the second objective, spatial variations in metal contents were mainly associated with sediment composition and environmental characteristics such as water flow velocity. In turn, temporal variations were mainly related to rainfall, which tends to increase the input of metals to the aquatic environment through surface runoff. However, there was a delay in relation to rainfall and increased concentrations of metals in the sediment, which indicates a temporal offset for metals to accumulate in the sediment. In addition, metals such as Cu, Pb, V and Zn were shown to be anthropogenically enriched in the Rio Doce sediments during the study period. However, these elements do not exceed concentrations from which negative effects on organisms are expected.

BANKING MEMBERS:
Externo à Instituição - JOEL BARBUJIANI SIGOLO - USP
Interno - ***.819.324-** - JULIO ALEJANDRO NAVONI - UFRN
Presidente - 1298966 - RAQUEL FRANCO DE SOUZA