title: Aminocyclopyrachlor sorption-desorption and leaching from three Brazilian soils.
abstract: This study aimed to evaluate the sorption-desorption and leaching of aminocyclopyrachlor from three Brazilian soils. The sorption-desorption of14C-aminocyclopyrachlor was evaluated using the batch method and leaching was assessed in glass columns. The Freundlich model showed an adequate fit for the sorption-desorption of aminocyclopyrachlor. The Freundlich sorption coefficient [Kf (sorption)] ranged from 0.37 to 1.34 µmol(1-1/n)L1/nkg-1and showed a significant positive correlation with the clay content of the soil, while the Kf (desorption)ranged from 3.62 to 5.36 µmol(1-1/n)L1/nkg-1. The Kf (desorption)values were higher than their respective Kf (sorption), indicating that aminocyclopyrachlor sorption is reversible, and the fate of this herbicide in the environment can be affected by leaching. Aminocyclopyrachlor was detected at all depths (0-30 cm) in all the studied soils, where leaching was influenced by soil texture. The total herbicide leaching from the sandy clay and clay soils was <0.06%, whereas, ∼3% leached from the loamy sand soil. The results suggest that aminocyclopyrachlor has a high potential of leaching, based on its low sorption and high desorption capacities. Therefore, this herbicide can easily contaminate underground water resources.
authors.affiliation: a Center of Nuclear Energy in Agriculture , University of São Paulo , Piracicaba , SP , Brazil.
authors.forename: Jeane G
authors.initials: JG
authors.lastname: Francisco
authors.affiliation: a Center of Nuclear Energy in Agriculture , University of São Paulo , Piracicaba , SP , Brazil.
authors.forename: Kassio F
authors.initials: KF
authors.lastname: Mendes
authors.affiliation: a Center of Nuclear Energy in Agriculture , University of São Paulo , Piracicaba , SP , Brazil.
authors.forename: Rodrigo F
authors.initials: RF
authors.lastname: Pimpinato
authors.affiliation: a Center of Nuclear Energy in Agriculture , University of São Paulo , Piracicaba , SP , Brazil.
authors.forename: Valdemar L
authors.identifier: http://orcid.org/0000-0002-6618-6579
authors.initials: VL
authors.lastname: Tornisielo
authors.affiliation: b Department of Agronomy , University of Mato Grosso State , Alta Floresta , MT , Brazil.
authors.forename: Ana C D
authors.initials: ACD
authors.lastname: Guimarães
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates; D001938:Brazil; D000077215:Clay; D006540:Herbicides / Q000032:analysis / Q000737:chemistry; D011743:Pyrimidines / Q000032:analysis / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D006540:Herbicides; D011743:Pyrimidines; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C560341:aminocyclopyrachlor; D000077215:Clay
keywords: Herbicide transport; pyrimidine carboxylic acid; retention; tropical soils