Banca de DEFESA: THAIS PAULA DE ARAUJO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : THAIS PAULA DE ARAUJO
DATE: 10/08/2022
TIME: 09:00
LOCAL: video conferencia
TITLE:

EVALUATION OF THE TOXICITY OF NITROGENATED COMPOUNDS IN FISH IN THE CONTEXT OF GLOBAL CHANGES

KEY WORDS:

global changes, toxicity, fish

PAGES: 60
BIG AREA: Multidisciplinar
AREA: Biotecnologia
SUMMARY:

Global changes have directly impacted aquatic ecosystems, and driven by human activities can cause irreversible damage to biological diversity. Among the consequences of these global changes are the excess of nutrients in lakes, associated with agricultural activities, mainly through the use of fertilizers and nitrogenous pesticides, and climate change, such as increased temperature, changes in rainfall and, consequently, a reduction in lake depth. In order to investigate the effects of these changes on fish, two studies were conducted: the first was reviewing the literature to address the effects of nitrogen compounds (nitrite, nitrate and ammonia) and how the physicochemical parameters influence their toxicity, and the second was a case study using Hoplias malabaricus liver in a lake impacted by the accumulation of nitrogenous compounds. The effects of nitrogen compounds can be influenced by physicochemical parameters, and may have synergistic, antagonistic or protective effects. High salinities showed a protective effect on ammonia and nitrite toxicity, hypoxia and low pH were able to intensify the effects caused by ammonia and nitrate, with synergistic effects. The increase in temperature caused distinct effects among the nitrogen compounds, with synergistic effects when fish were simultaneously exposed to ammonia, and antagonistic effects when exposed to nitrite and nitrate. Hardness also influenced toxicity, and its effects are dependent on the species under study. In the second study, prolonged droughts have directly impacted aquatic fauna. The specimens of Hoplias malabaricus showed histological alterations and the occurrence of apoptosis that are associated with the detoxification process in the liver due to the accumulation of nitrogen compounds in the Carioca lagoon. The increase in the number and area of melanomacrophagic centers may be associated with fish exposure to pollutants such as ammonia and nitrite. Histological, histochemical, and immunohistochemical biomarkers proved to be bioindicators of environmental impact.

BANKING MEMBERS:
Presidente - 2875448 - RALPH GRUPPI THOME
Interno - 1908201 - JOAQUIM MAURICIO DUARTE ALMEIDA
Externa à Instituição - CAMILA MARIANGELA PACHECO