Effects of Organic Matter and Clay Content in Soil on Pesticide Adsorption Processes

Abstract

The effect of organic matter and clay content on the adsorption of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was studied. In order to determine whether and to what degree different soil properties affect the process of determination of selected pesticides, three soils with different clay and organic matter contents were used. An optimized liquid-solid extraction procedure followed by SPME measurement was applied to analyse the selected pesticides in soil samples. Detection and quantification were done by gas chromatography-mass spectrometry (GC/MS). Relative standard deviation (RSD) values for multiple analyses of soil samples fortified at 30 μg/kg of each pesticide were below 19%. Limits of detection (LODs) for all compounds studied were less than 2 μg/ kg. The results indicate that soils with different physico-chemical properties have different effects on the adsorption of most pesticides, especially at higher concentration levels.

Proučavan je uticaj sadržaja organske materije i gline u uzorcima zemljišta na procese adsorpcije atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena. U cilju utvrđivanja da li i u kojoj meri različite zemljišne karakteristike utiču na adsorpciju proučavanih pesticida, a time i na njihovo određivanje, izabrana su tri zemljišta sa različitim sadržajem organske materije i gline. Za određivanje pomenutih pesticide u uzorcima zemljišta korišćena je optimizovana tečno-čvrsta ekstrakciona procedura u kombinaciji sa metodom mikroekstrakcije u čvrstoj fazi (SPME). Detekcija i kvantifikacija analita je vršena gasno-masenim spektrometrom (GC/MS). Vrednosti relativnih standardnih devijacija (RSDs) višestruko ponovljenog merenja uzorka obogaćenog do 30 μg/kg svakog pesticida su ispod 19%. Granice detekcije (LODs) za sve pesticide i zemljišta uključena u ispitivanje su bila ispod 2 μg/kg. Rezultati ukazuju da zemljišta različitih fizičko-hemijskih karakteristika imaju različit uticaj na sorpciju za većinu proučavanih jedinjenja, što je naročito izraženo kod većih koncentracija.