Abstract

CUERVO, Jairo Leonardo  and  FUENTES, Cilia Leonor. Mineralization and sorption of ¹⁴C-glyphosate in samples from three soil types collected in El Espinal, Colombia. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2014, vol.38, n.148, pp.287-297. ISSN 0370-3908.

We studied the mineralization and sorption of ¹⁴C-glyphosate in samples of three soil types from El Espinal municipality (Tolima) with different land use history: (1) soil subjected to pesticide use and sowing of annual crops (mainly rice) during 30 years; (2) soil in rest for five years with sown grassland, and (3) secondary semidry forest soil without record of pesticide use. The ¹⁴C-glyphosate mineralization in the soil samples was effected in biometers. One hundred and six days after the incubation with the herbicide, 53%, 38% and 23% of the glyphosate was mineralized in the forest, grass and rice-crop soil samples, respectively. The glyphosate sorption phenomenon (adsorption-desorption) was adjusted to the Freundlich model. The Kd_des values for forest, grassland and rice-crop soil samples were 17.00, 1.83 and 3.10, respectively. The low rate of glyphosate mineralization allowed us to infer that the glyphosate can become an environmental pollution problem due to its high persistence in the soil.

Keywords : Herbicides; microorganisms; radiomarked; pollution; rice.

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