Banca de DEFESA: Nayara Luiz Pires

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Nayara Luiz Pires
DATE: 24/08/2023
TIME: 14:00
LOCAL: (https://www.microsoft.com/pt-br/microsoft-teams/log-in
TITLE:

“Evaluation of the presence of agricultural inputs in water resources of the Alto Jardim River Hydrographic Unit (DF): development of methods and water quality”

KEY WORDS:

fertilizer; pesticide; UHPLC-MS/MS, surface water; groundwater; Rio Preto hidrographic basin

PAGES: 180
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

The use of pesticides and fertilizers in agriculture in the Brazilian Cerrado is intense and excessive amounts of these compounds can affect and alter water quality. The objective of this study was to evaluate the presence of these inputs in water resources, as well as to develop analytical methods and analyze the water quality of the Alto Rio Jardim Hydrographic Unit (UHARJ). Total phosphorus, pH and dissolved ions of nitrate (NO₃^-), nitrite (NO₂^-), ammonium (NH₄⁺), phosphate (PO₄³^-) and potassium (K⁺) were measured in 207 groundwater samples (2014/2015 and 2019/2020) and 23 surface water samples (2019/2020) collected in the UHARJ. In general, a smaller number of positive samples for the analyzed ions was found in groundwater samples from the 2014/2015 period, but with higher average levels of NH₄⁺ (0.463 and 0.454 mg L^-1, dry and rainy seasons, respectively) when compared to 2019/2020 (0.199 and 0.176 mg L^-1). NH₄⁺ levels in the surface water sample were higher in the dry season (0.106 mg L^-1) than in the rainy season (0.59 mg L^-1). A method for analyzing glyphosate, AMPA and glufosinate was validated on LC-MS/MS with an LOQ of 0.0025 μg L⁻¹ (after lyophilization), 90 surface water and 52 groundwater samples collected at BHRP in 2021/2022 were collected. All groundwater samples were positive for glyphosate (up to 1.5868 μg L⁻¹, dry) and AMPA (up to 0.2751 μg L⁻¹, dry). A total of 27 water samples were positive for glyphosate (up to 0.0236 μg L⁻¹) and 31 samples for AMPA (up to 0.0086 μg L ⁻¹), of which more than 70% were collected in the dry season. Glufosinate was detected in five samples, four from groundwater (up to 0.0256 μg L^-1). A multiresidue method (lyophilization/UHPLC-MS/MS) was developed for the determination of 78 pesticides, and applied for the analysis of 68 samples collected at UHARJ (2021/2022), 27 of groundwater and 7 of surface water. Atrazine and its metabolites, carbendazim and fipronil were the most detected pesticides in the samples and 2,4-D the pesticide found at the highest level (1.045 µg L^-1; groundwater, dry). The levels found in the samples are much lower than the maximum levels established by Brazilian legislation. However, constant monitoring is necessary, demanding sensitive methods that allow detecting the very low levels of these pesticides in the water.

COMMITTEE MEMBERS:
Externo à Instituição - RENATO ZANELLA - UFSM
Externo à Instituição - GIULIANO MARCHI
Presidente - ***.875.257-** - EDUARDO CYRINO DE OLIVEIRA FILHO - EMB/CENARGEN
Interno - 1644727 - LUIZ FABRICIO ZARA
Externo ao Programa - 2189333 - RICARDO TEZINI MINOTI - null