Sorption, Degradation and Leaching of the Phenoxyacid Herbicide MCPA in Two Agricultural Soils
Edgar Hiller1, Slavomír Čerňanský2, Lenka Zemanová1
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1Department of Geochemistry, Faculty of Natural Sciences, Comenius University in Bratislava,
2Department of Ecosociology and Physiotactics, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, 842 15 Bratislava 4, Slovak Republic
Pol. J. Environ. Stud. 2010;19(2):315–321
MCPA is the phenoxyacid herbicide widely used for weed control in cereals in Slovakia. However, little is known on the processes governing the environmental fate of MCPA in soils from Slovakia. Laboratory experiments were performed to evaluate the sorption, desorption, degradation, and leaching behavior of MCPA in two agricultural soils with high sand content and different soil organic carbon content. The extent of MCPA sorption was higher in chernitsa than that in regosol, in accordance with the higher organic carbon content of the former soil than the latter. MCPA was readily desorbed from soils with 10 mmol l-1 CaCl2 solution with the desorption rate ranging from 44.5 to 77.5% of the sorbed MCPA. The half-life values showed that the degradation of MCPA was fast in chernitsa (t1/2 = 2.2 days) and almost six times faster than in regosol (t1/2 = 11.7 days). Leaching tests, performed in manually packed soil columns, indicated that MCPA was more mobile in regosol than in chernitsa with 16.44% of the applied MCPA recovered in the leachates of regosol, and 1.12% found in the leachates of chernitsa. Thus, differences in the leaching behavior of MCPA coincided well with the results of the batch sorption and degradation experiments.