Abstract

MADRIGAL MONARREZ, Ismael et al. Pesticide sorption and desorption from soils having different land use. Ing. Investig. [online]. 2008, vol.28, n.3, pp.96-104. ISSN 0120-5609.

This study was carried out within the framework of a multidisciplinary project for evaluating buffer zones for combating pesticide contamination of surface water. Such areas are effective in removing pesticides transported by run-off; however, little information is available about the fate of the pesticides so intercepted. Two herbicides having contrasting properties (isoproturon, moderately hydrophobic (log K_ow = 2.5), diflufenican, strongly hydrophobic (log K_ow = 4.9)) and isopropylaniline (an isoproturon metabolite) were used for characterising sorption and desorption from soil having three different land uses: grass buffer strip, woodland and cultivated plot. The experiments were carried out in controlled laboratory conditions using isoproturon labelled with ¹⁴C in the benzene ring. The results demonstrated that diflufenican and isopropilaniline retention was more significant than isoproturon in three soils. The three molecules’ K_d values revealed that isoproturon and diflufenicanil retention was more important in woodland soil where carbon content was more significant (ZB 0-2: K_d IPU = 15.1 Ls kg^-1; K_d DFF = 169.2 Ls kg^-1). Isopropilanilina K_d was higher in grass buffer strip soil (BE 0-2: K_d IPA = 53.1 L kg^-1). These differences were related to different organic matter content and nature according to the type of land use.

Keywords : agrochemical product; pesticide; contamination; water; sorption; desorption; organic matter; buffer zone.

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