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Master's Dissertation
DOI
https://doi.org/10.11606/D.11.2019.tde-20191218-124840
Document
Author
Full name
Brigida Pimentel Villar de Queiroz
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1997
Supervisor
Title in Portuguese
Biodegradação de 14C-atrazina em condições semi controladas
Keywords in Portuguese
BIODEGRADAÇÃO
CARBONO-14
HERBICIDAS
LATOSSOLO VERMELHO-ESCURO
RADIOTRAÇADORES
Abstract in Portuguese
A biodegradação da atrazina radiomarcada uniformemente em seus carbonos do anel, foi avaliada em condições semi controladas. Amostras de 200g do solo - Latossolo Vermelho-Escuro, Álico, A moderado, textura média, tratadas com uma solução de atrazina com atividade de 135,42kBq e dose de 2mg i.a./Kg de solo (5L/ha) foram colocadas em frascos Erlenmeyers de 300ml de capacidade e a umidade ajustada para 75% da capacidade de campo. Estes frascos foram enterrados na Estação Experimental do Lisímetro do CENA/USP onde se iniciou, ao mesmo tempo, uma plantação de milho. O 14CO2 desprendido pela ação de microrganismos degradadores de atrazina, foi avaliado a cada quinze dias, durante 150 dias. Os resíduos formados no solo durante o período de incubação foram determinados, em termos de dessorção utilizando cloreto de cálcio, extração com os solventes acetonitrila/água (8:2 v/v) e resíduos ligados por combustão. O solo extraído foi fracionado com pirofosfato de sódio e os resíduos ligados nas frações humina, ácidos húmico e fúlvico foram determinados por cintilometria líquida. Ao final do período de incubação de 150 dias 14CO2 desprendido, alcançou 36% da atividade total aplicada, os resíduos ligados no total de 34% ficaram distribuídos na fração humina 63,26%, ácido fúlvico 29,91% e ácido húmico 6,83%. Os metabólitos presentes nas frações de resíduos dessorvidos e extraídos, foram identificados através de cromatografia de camadas delgada. Após 150 dias de incubação os resíduos formados nas frações dessorvidas foram 44% de hidroxiatrazina, 3,28% de desisopropilatrazina e 52,72% de atrazina e nas frações extraídas foram 16,22% de hidroxiatrazina, 2,25% de desisopropilatrazina, 2,24% de desetilatrazina e 79,29% de atrazina.
Title in English
Biodegradation of 14C-atrazine under outdoor conditions
Abstract in English
Uniformily 14C-ring labeled atrazine (5L/ha) was applied to a Typical Hapludox Brazilian Soil sample which was incubated under outdoor conditions. Samples of 200g (dry weight base) of fresh soil were distributed in Erlenmeyer flasks and the moisture was adjusted for 2/3rds af the soil field capacity. The flasks were then buried in the Lysimeter Station when they were incubated. The experiment started jointly with a com planting. The 14C02 was analyzed every 15 day, during a period of 150 days. The desorbed, extracted and bound residues were analyzed. The extracted soil was fractionated and the residues in the humin, fulvic and humic acids were determined. At the end of the incubation period (150 days), the 14C02 evolved reached up to 36% of the total applied activity, the bound residues were detected in about the same (34%) during the inoculation period, and were distributed in the fractions of fulvic acids (29,91%), humic acids (6,83%) and humin (63,26%). The metabolites formed in the desorbed residues and in the extracted residues were determined using thin layer chromathography with 14C-detector. After 150 days incubation, desorbed soil residues were identified as atrazine (52,72%), hydroxiatrazine (44%) and desisopropilatrazine (3,28%). The extractable residues contained atrazine (79,29%), hydroxiatrazine (16,22%), desisopropilatrazine (2,25%) and desetylatrazine (2,24%).
 
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Publishing Date
2019-12-19
 
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