Mobility of a siliconepolyether studied by leaching experiments through disturbed and undisturbed soil columns

The studied substance, a siliconepolyether, is intended for use as an additive (wetting agent) in herbicide formulations. It had been tested before for adsorption and desorption in batch experiments and is now submitted to leaching studies through columns with both disturbed and undisturbed soil in order to assess its mobility and, at the same time, evaluate different methods of soil column preparation. The substance showed mobility to at least 20 cm under both types of column preparation. This contradicts earlier results obtained by adsorption and desorption batch experiments (isotherms) and soil thin-layer chromatography which found the studied substance to be rather immobile. Possible explanations are discussed, whilst stressing that the use of batch experiments and 'synthetic systems' alone in mobility assessments of chemicals might lead to wrong conclusions. During the study, phenomena have been observed which indicate degradation of the tested siliconepolyether. (C) 1998 Elsevier Science B.V. All rights reserved.