Resumen

GONZALEZ-MARQUEZ, Luis Carlos  y  HANSEN, Anne M.. Effect of salinity on adsorption of a herbicide in agricultural soils. Rev. Int. Contam. Ambient [online]. 2014, vol.30, n.2, pp.191-199. ISSN 0188-4999.

To understand the effect of salinity on the adsorption of the herbicide atrazine in two soils from a Mexican agricultural area, the influence of sodium and calcium chloride concentrations were determined. Adsorption experiments were performed with soil samples from Irrigation District 063 (DR 063), Guasave, Sinaloa, Mexico, suspended in 10 mM CaCl₂, in the presence of several concentrations of different electrolytes and atrazine (0.01, 0.05, 0.1, 0.5 and 1.0 mg/L) with radioactive tracer (347.4 Bq U-ring-¹⁴C, Sigma Chemical Company, St. Louis, MO, USA). It was found that for all the electrolytes, the time required to reach equilibrium adsorption of atrazine was less than 24 h and the adsorption isotherms were adjusted to Freundlich model. The presence of sodium in the aqueous solution favored the adsorption and inhibited desorption of atrazine in soils. Increasing the concentrations of sodium and calcium to about 40 mM and 60 mM, respectively, did not significantly affect (P <0.05) the adsorption of atrazine. However, there were differences in desorption of the herbicide with the increase of salts concentrations. The results of this study indicate that increased salinity, mainly caused by increased sodium concentrations in the soil-water system, has important effects on the fate of atrazine, due to salinization of soils favors the adsorption of atrazine, and inhibits its desorption. It is important to consider these properties when application options are analyzed as well as in the management and remediation of soils contaminated with atrazine.

Palabras llave : atrazine; sodium chloride; calcium chloride; adsorption; desorption; natural attenuation.

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