Open AccessAdsorption mechanisms of atrazine isolated and mixed with glyphosate formulations in soil
Author(s) -
Matheus de Freitas Souza,
Ana Cláudia Langaro,
Ana Beatriz Rocha de Jesus Passos,
Hamurábi Anízio Lins,
Tatiane Severo Silva,
Vander Mendonça,
Antônio Alberto da Silva
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0242350
Subject(s) - atrazine , sorption , glyphosate , desorption , adsorption , chemistry , freundlich equation , environmental chemistry , pesticide , leaching (pedology) , soil water , agronomy , environmental science , biology , soil science , organic chemistry
In Brazil, the atrazine has been applied frequently to join with glyphosate to control resistant biotypes and weed tolerant species to glyphosate. However, there are no studies about atrazine's behavior in soil when applied in admixture with glyphosate. Knowledge of atrazine's sorption and desorption mixed with glyphosate is necessary because the lower sorption and higher desorption may increase the leaching and runoff of pesticides, reaching groundwaters and rivers. Thereby, the objective of this study was to evaluate the adsorption mechanisms of atrazine when isolated and mixed with glyphosate formulations in a Red-Yellow Latosol. The maximum adsorbed amount of atrazine in equilibrium ( q e ) was not altered due to glyphosate formulations. The time to reach equilibrium was shortest when atrazine was mixed with the Roundup Ready ® ( te = 4.3 hours) due to the higher adsorption velocity ( k 2 = 2.3 mg min -1 ) in the soil. The highest sorption of atrazine occurred when mixed with the Roundup WG ® , with the Freundlich sorption coefficient ( Kf ) equal to 2.51 and 2.43 for both formulation concentrations. However, other glyphosate formulations did not affect the sorption of atrazine. The desorption of atrazine was high for all treatments, with values close to 80% of the initial adsorbed amount, without differences among isolated and mixed treatments. The change in the velocity and capacity of sorption for the atrazine mixed with some glyphosate formulations indicates that further studies should be conducted to identify the mechanisms involved in this process.