A Comparison of Five Pesticides Adsorption and Desorption Processes in Thirteen Contrasting Field Soils

George E. Brown, Jr. Salinity Laboratory, USDA-ARS, 450 West Big Springs Road, Riverside, CA 92507-4617, USA.
Chemosphere (Impact Factor: 3.34). 12/2005; 61(5):668-76. DOI: 10.1016/j.chemosphere.2005.03.024
Source: PubMed


Batch adsorption and desorption experiments were performed using thirteen agricultural soil samples and five pesticides. Experimental data indicated a gradient in pesticide adsorption on soil: trifluralin > 2,4-D > isoproturon> atrazine > bentazone. Atrazine, isoproturon and trifluralin adsorption were correlated to soil organic matter content (r2 = 0.7, 0.82, 0.79 respectively). Conversely, bentazone adsorption was governed by soil pH (r2 = 0.68) while insignificant effect has been shown in the case of 2,4-D. Multiple linear regressions were used to combine relationships between the various soil parameters and the Freundlich adsorption coefficient (K(f)) of each pesticide. Then desorption was assessed since it may reflect some of the interactions involved between the pesticides and the soil components. Adsorbed molecules were released into aqueous solution in the following order: bentazone > atrazine> isoproturon> 2,4-D > trifluralin. The occurrence of hysteresis did not allow an accurate interpretation of the pesticide desorption data because of the possible interplay of several processes.

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Available from: Arnaud Boivin, Sep 17, 2014
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    • "For instance, relatively low pH values (pH=5.4) were said to cause stronger hydrogen bonding when compared to neutral or alkali pH conditions (Boivin et al. 2005; Thangavadivel et al. 2011). As can be seen, the factors affecting sorption/desorption. "
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    • "[25] In well-structured soils, preferential flows speed the movement of water and atrazine through the soil; [26] it has also been shown that SOM helps to retain atrazine in the soil. [27] Another process that influences the amount of atrazine in the soil is atrazine degradation . Atrazine is an organic component and its degradation depends on the microbial biomass of the soil, which in turn is affected by agronomic practice. "
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    • "Studies have reported extensively on the fate and transport of Pesticides and herbicides from agricultural sources in ground and surface water (Brown et al., 1995; Brown et al., 2002; EA 2003b and Fletcher et al., 2004, Boivin et al., 2005). Chilton et al., 2005 and Buss et al., 2006 reported that sorption and biodegradation are possible attenuation processes of Mecoprop in Landfill liners and aquifer. "
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