Data/hora: 23/09/2024 18:03:25

Biblioteca(s): 	Embrapa Instrumentação.	
Data corrente: 	22/12/1999	
Data da última atualização: 	22/12/1999	
Autoria: 	TRAGHETTA, D. G.; SPOSITO, G.; VIEIRA, E. M.; MACHADO, S. A. S.; MAZO, L. H.; AVACA, L. A.; VAZ, C. M. P.; CRESTANA, S.; MARTIN NETO, L.	
Afiliação: 	USP-IFSC; University of California, Berkeley; USP-IQSC; EMBRAPA-CNPDIA.	
Título: 	Degradation and mechanism of sorption of atrazine in soil organic matter fractions.	
Ano de publicação: 	1996	
Fonte/Imprenta: 	In: IUPAC GARP WORKSHOP PN PESTICIDES: USES AND ENVIRONMENTAL SAFETY IN LATIN AMERICA, Oct. 1996, Sao Paulo, SP. Book of abstracts... Sao Paulo; Sociedade Brasileira de Quimica, 1996.	
Páginas: 	p. 70. Ref.P-08.	
Idioma: 	Inglês	
Conteúdo: 	The herbicide atrazine (2-chloro-4-ethylamino-6-isopropilamino-1,3,5-triazine) has been widely used in Brazil and the world, mainly for controlling weeds in corn culture. Its half-life varies between 1,5 month and 5 years. Among the soil fractions, the organic matter is the most important for sorption of non-polar herbicides. For atrazine (AT), many authors has shown that humic substances are the principal site for its adsorption on soil and therefore they play an important role in the degradation process. In this work quantitative and qualitative analysis about sorption and degradation of atrazine on soil organic matter components (humic acids-HA and fulvic acids-FA) were performed extending previous studies [1]. Spectroscopic techniques used were electronic paramagnetic resonance (EPR), electronic absorption UV-visible and infrared (FTIR). For quantitative analysis an electroanalytical method, differential pulse polarography (DPP) was used. The humic substances has shown to be catalysts in degradation of atrazine. Spectroscopic data (EPR,FTIR) showed that sorption of atrazine occurred on humic and fulvic acids, from tropical sites, through hydrogen bond and proton-transfer, but no through electron-transfer as generally suggested in literature of s-triazines [2]. At low pH's, near pKa atrazine (1,68), degradation of AT to hydroxy-atrazine (OH-AT) is relatively high, while in higher pH's many occur degradation through proton-transfer mechanism (Bronsted acidity) between atrazine and humic substances...	
Palavras-Chave: 	Agricultural instrumentation; Degradacao; Herbicidas; Instrumentacao agropecuaria.	
Thesagro: 	Atrazina; Matéria Orgânica; Solo; Sorção.	
Thesaurus Nal: 	atrazine; degradation; herbicides; organic matter; soil; sorption.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Instrumentação (CNPDIA)	
Exemplares: 	CNPDIA - (5601-1) - UPC - SP - -- - PROCI-96.00187 -  - 1996.00187 - DIS