Influence of surfactants on the sorption of two chloroacetanilide in an Romanian chernozem soil.
Pesticides have been extensively used in modern agriculture. Due to the prevalent use, there have been serious problems generated by pesticides wastes which could eventually endanger water resources and human health. The development of technologies for the decontamination of soils and waters polluted by hydrophobic organic compounds has encouraged research into the use of non-ionic surfactants as potential agents for the enhanced solubilization and removal of contaminants from soils and sediments. Sorption of two chloroacetanilide herbicides, acetochlor and metolachlor was studied on a representative chernozem soil of the Main Agricultural Research Station Ezareni belonging to the "Ion Ionescu de la Brad" University of Agriculture and Veterinary Medicine lasi, Romania, in the presence and absence of surfactants. Three different non-ionic surfactants were selected: Tween-20, Synperonic 91/5 and Silwet L-77, to verify the influence of their presence on herbicide sorption at different concentrations. Our results showed that the sorption of the studied herbicides within the soil-water-non-ionic surfactant system was influenced by the presence of non-ionic surfactants. The n values obtained were lower than 1 for all pesticide-surfactant combinations, which indicates that the amount of acetochor and metolachlor sorbed decreased with an increase in pesticide concentration. The sorption of acetochlor increased in the following order: Acetochlor+Synperonic 91/5 < Acetochlor < Acetochlor+Tween-20 < Acetochlor+Silwet L-77. In the case of metolachlor+Synperonic and metolachlor+Silwet L-77, the Kf values were significantly higher than the Kf value of metolachlor+Tween-20 on soil, where a lower Kf value could be observed with however a higher n value which indicate a higher sorption capacity at higher concentrations.
Department of Soil Management, Faculty of Agriculture, "Ion Ionescu de la Brad" University of Agricultural Sciences and Veterinary Medicine, Iasi 700490, Romania.
I G
IG
Coroi
T
T
De Wilde
M S
MS
Cara
G
G
Jitareanu
W
W
Steurbaut
D000081:Acetamides / Q000737:chemistry*; D000327:Adsorption; D006540:Herbicides / Q000737:chemistry*; D012383:Romania; D012987:Soil / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014052:Toluidines / Q000737:chemistry*
D000081:Acetamides; D006540:Herbicides; D012987:Soil; D013501:Surface-Active Agents; D014052:Toluidines; C043377:acetochlor; C051786:metolachlor