Name: EDVAR JÚNIOR RONCETTI COELHO
Type: PhD thesis
Publication date: 09/12/2021
Advisor:
Name |
Role |
|---|---|
| Silvia Tamie Matsumoto | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Diolina Moura Silva | Internal Examiner * |
| Elias Terra Werner | Internal Alternate * |
| Geraldo Rogério Faustini Cuzzuol | Internal Examiner * |
| MARIA APARECIDA MARINS MORALES | External Examiner * |
| MARIANA MOROZESK | External Alternate * |
| MARINA MARQUES BONOMO | External Examiner * |
| Silvia Tamie Matsumoto | Advisor * |
Summary: Water ecosystems are extremely important for carrying out various human
activities, such as water public supply and for irrigation and food production.
The Jucu River, the object of study on this, is located in the state of Espírito
Santo (Brazil) and plays this fundamental socioeconomic role for the region.
This study aimed to evaluate the environmental water quality of the Jucu River,
through surface water and sediment samples in six stations along the river in
the dry and rainy periods, to understand the impact of rainfall on the quality of
water used for human supply and agriculture. The elutriate was obtained from
the sediment samples for carrying out the tests. Physical and chemical
parameters of water samples were measured and elemental quantification of
aluminum, cadmium, lead, cobalt, chromium, copper, iron, magnesium,
manganese, nickel, and zinc in water and elutriate samples were carried out. In
addition to the abiotic analyses, bioassays were performed on specimens of
Allium cepa exposed to water and elutriate samples, WHERE the germination
index, root growth index, mitotic index, chromosomal alteration index,
mutagenicity index and evaluation of the Biochemical and biotransformation
biomarkers of the antioxidant system (superoxide dismutase, catalase,
glutathione S-transferase, glutathione, and lipid peroxidation) were evaluated.
The results revealed total nitrogen levels above the limits established by
legislation in the first sample and high turbidity levels in the second sample,
both probably influenced by rainfall during the collection periods. The results of
the elementary quantification alert that there is contamination of the water and
elutriate samples with values above those allowed by the legislation for Al, Fe,
Mn, and Cu in all stations of the two samplings and that all other elements were
superior to the legislation in the second sampling of elutriate (rainy season). It is
suggested that Al and Fe contamination is due to the pedological characteristic
of the Jucu River watershed, predominantly composed of red-yellow latosol and
cambisol soils. However, the contamination was possibly originated from
agricultural and livestock activities in the region and also due to the input of
untreated effluents into the river. The bioassays revealed a potential phytotoxic,
cytotoxic, mutagenic, and genotoxic effect in most samples, intensified in the
rainy season, and these effects can be correlated to the metals quantified in the
samples and/or to climate change with changes in precipitation. Alterations in
antioxidative metabolism were also observed in most treatments, evidenced by
lipid peroxidation observed in the second water sample and the first elutriate
sample. These results demonstrate that the water quality of the Jucu River is
compromised for human supply, and irrigation and that there is contamination
by metals with bioavailability influenced by periods of rain and drought that can
cause stressful effects on aquatic biodiversity and the human population that
interacts with this ecosystem.
Keywords: heavy metals rainfall antioxidant enzymes Allium cepa test
oxidative stress.
