Pesticide sorption onto aquifer sediments

This study aims to investigate the nature and extent of sorption of herbici des by sandy aquifer sediments. Three phenylurea herbicides (linuron, diuro n and isoproturon), two triazine herbicides (atrazine and simazine), and on e phenylurea metabolite and one triazine metabolite (dichlorophenylurea and desethylatrazine, respectively) were investigated. The approaches taken we re: (1) batch experiments to determine Kd values followed by simple Linear regression against sediment properties, (2) theoretical consideration of so rption, using partial molar free energies and binding-site calculations. Th e results demonstrated that the sands had a powerful sorption capacity for all of the compounds studied. Sorption of the phenylurea compounds indicate d a probable dual-mode sorption process in which partitioning and site-dire cted interactions occur. (C) 1998 Elsevier Science B.V. All rights reserved .