Avaliação de água e sedimentos do rio Jucu-ES por meio de marcadores citogenéticos e bioquímicos.
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Data
2021-12-09
Autores
Coelho, Edvar Junior Roncetti
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Universidade Federal do Espírito Santo
Resumo
The Jucu River, the object of this study, 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. 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 the 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, reduced 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.
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Enzimas antioxidantes , estresse oxidativo , metais pesados , pluviosidade , teste do Allium cepa