Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2001
Publication Date: 4/9/2002
Citation: Locke, M.A., Reddy, K.N., Gaston, L.A., Zablotowicz, R.M. 2002. Adjuvant modification of herbicide interactions in aqueous soil suspensions. Soil Science.
Interpretive Summary: Soil that has been contaminated by pesticides may need remediation measures to restore it to original conditions. A study was conducted to assess the use of several adjuvants as a remediation tool to facilitate removal of cyanazine, atrazine, or norflurazon herbicides from soil. Results showed that nonionic and anionic adjuvants have potential to remove atrazine and cyanazine from contaminated soils of varying texture and organic matter contents, but they were not effective for norflurazon. Although adjuvants may be useful in remediating some herbicide contaminated soils, the utility of a given adjuvant for remediation is very dependent on both herbicide and soil characteristics.
Technical Abstract: The effects of adjuvants on the sorption and desorption of cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]- 2- methylpropanenitrile), atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)- 1,3,5-triazine-2,4,-diamine), and norflurazon (4-chloro-5- (methylamino)-2-(3-(trifluromethyl)phenyl)-3(2H)-pyridazinone) in several soils were studied for the potential of use in remediating herbicide-contaminated soils. The soils evaluated represented a wide range of soil texture, organic carbon, and pH. Sorption of 14**C- labelled herbicide was determined using batch equilibrium methods (equilibrated in water or adjuvant at 2.5 gL**-1). Adjuvants used were nonionic, cationic, and anionic. Desorption at two initial herbicide concentrations was done with water or adjuvant. Sorption of all herbicides increased with increasing clay content. Adjuvants generally increased the water solubility of these herbicides. Cyanazine and atrazine sorption was decreased with adjuvant, whereas norflurazon sorption was increased with nonionic adjuvant compared to water alone. Similarly, for cyanazine and atrazine, total percentage of desorption was greater with adjuvant, while norflurazon desorption with a nonionic adjuvant was less than with water. Results from these studies indicate that adjuvants may be useful in remediating soils contaminated with some herbicides. However, adjuvant effects on sorption-desorption can be herbicide- and soil-specific.