STUDY OF THE EFFECT OF EXOGENOUS ORGANIC-MATTER ON THE MOBILITY OF PESTICIDES IN SOILS USING SOIL THIN-LAYER CHROMATOGRAPHY

The effect of soil amendment using urban compost, agricultural organic amendments and surfactants on the mobility of two sparingly-soluble p esticides - diazinon and linuron - was studied by soil thin-layer chro matography. The modifications in R(F) values due to the addition of th e amendments were similar for both pesticides. No significant correlat ion was found between the R(F) values and the content of total organic carbon in the amended soils. This fact indicated that not only the or ganic carbon content of amended soils but also the amendment nature, s pecially their content in soluble fractions must play a very important role in the pesticide mobility. The surfactants gave rise to importan t alterations in pesticide mobility; the pesticides changed from being slightly mobile in natural soil to being immobile in the soil sample modified with tetradecyltrimethylammonium bromide and to being mobile in the soil sample amended with sodium dodecyl sulphate.