Resumo

GONZALEZ-MARQUEZ, Luis Carlos  e  HANSEN, Anne M.. Adsorption and mineralization of atrazine and their relationship with soil parameters in the irrigation distict 063 Guasave, Sinaloa. Rev. mex. cienc. geol [online]. 2009, vol.26, n.3, pp.587-599. ISSN 2007-2902.

The effect of soil properties on the natural attenuation of the herbicide atrazine was investigated in soil samples from the irrigation district 063. Adsorption and mineralization of atrazine in soils were evaluated using guidelines recommended by the Organization for Economic Cooperation and Development and radiolabeled (¹⁴C) atrazine. Confidence limits of 99% for mean of adsorption coefficients were 0.297-0.587 L kg^-1 and for the half life 2.0-5.8 yr. Atrazine adsorption isotherms were linear and adsorption coefficients of the herbicide were in the range reported in the literature for agricultural soils. The mineralization of atrazine in the soil samples was slow, an indicator that soil microorganisms are not adapted to the herbicide. This may be due to a reduction in the application rate of atrazine. Soil samples were characterized for sand, silt, clay contents, as well as organic matter, nitrates, ammonium, pH, and electrical conductivity. The correlation analysis between the natural attenuation of atrazine and soil properties shows a negative relationship between adsorption and soil depth as well as between atrazine mineralization and organic matter, ammonium and electrical conductivity. This means that atrazine is more mobile due to its lower adsorption in deeper soils and more persistent due to the increase in concentrations of such components. The results obtained in this work will be useful in the formulation of better scenarios of atrazine lixiviation in agricultural soils.

Palavras-chave : natural attenuation; agricultural region; half life; organic matter; fertilizers; salinity.

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