Name: GABRIEL SILVA NOGUEIRA
Type: MSc dissertation
Publication date: 25/02/2021
Advisor:
Name |
Role |
|---|---|
| EBERVAL MARCHIORO | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| EBERVAL MARCHIORO | Advisor * |
| FABIAN SÁ | External Examiner * |
| LUIZA LEONARDI BRICALLI | Internal Examiner * |
| RENATO RODRIGUES NETO | External Examiner * |
Summary: This work aims to investigate the seasonal variations of some physical-chemical
parameters and total metals with the chemical composition of geological and
unconsolidated formations in a hydrographic basin of an oceanic volcanic island in
a tropical climate. For this research, in the field, seasonal measurements of physical-
chemical parameters, monitoring of rainfall and gathering water samples were made.
In the laboratory, the samples were analyzed by ICP-MS to obtain the seasonal
variations of the metals (Ca, Mg, Zn, Sr, Al, Fe, Ba, Mn, Cu, V, Be, As, Cd, Ni, Pb,
Cr and Ag) in the sampling period. The data were tabulated and analyzed
statistically, relating them to the composition of the basin's rocks and soils and the
rainfall variation. The data were tabulated and analyzed statistically, correlating with
the composition of the basin's rocks and soils and the rainfall variation. The results
tip to the flow as a strong controller of the turbidity and concentration of suspended
sediments, which have a behavior similar and inverse to the electrical conductivity.
The values of the total dissolved solids were lower with the highest flow, indicating
that the higher flow is the predominance of physical erosion and the lower the
chemical denudation. The metal elements are seasonally divided into two main
groups, governed by Ca x Mg and Fe x Al, with calcium being the most abundant
element during the sample period, followed by Mg. Ca, Mg, Zn and Cu show greater
correlations with the accumulated rainfall over 40 days prior to sampled, indicating
a greater subsurface contribution, and the Ca x Mg reason values corroborate these
indications, ruling out the hypothesis of marine spray input to chemical composition
of the river waters analyzed. Fe and Al have a higher correlation with rainfall between
20 and 40 days accompanied by Be. Fe and Al have a higher correlation with rainfall
between 20 and 40 days accompanied by Be. Finally, this work points out the
existence of a correlation between the variations of the concentration of the total
metals in the surface water of the stream of a volcanic island in a tropical climate
with the oldest rainfall indexes, and the chemical denudation rates of the basin vary
according to the rainfall.
Keywords: Volcano Island. Geochemistry. Hydrogeochemistry. Trindade Island
