Leaching of mecoprop and dichlorprop in calcareous soil. Effect of the exogen organic matter addition in this process

Leaching studies of mecorprop (R,S)-2-(4-chloro-2-methylphenoxy)propanoic a cid, and dichlorprop, (R,S)-2-(4-chloro-2,4-dichlorophenoxy) propanoic acid , under saturated conditions were conducted in unamended and amended soil c olumns. The purpose of the study was to investigate the leaching of these h erbicides in three type of soils and the exogen organic matter effect on th is process. The leaching patterns could be related to variation in the soil texture and diffusion processes of the herbicides into micropores within t he walls of conducting pore. The leaching rate in the amended soil columns decreased with the addition of organic matter. The breakthrough curves (BTC ) of these herbicides in the leachates of the amended soil columns were wid er and more diffused than the ETC obtained for the corresponding unamended soil. The theoretical ETC overestimated the pore volume required for the di splacement of these pesticides from the soil column. This may be due to the differences in the adsorption process between the bacth and soil columns m ethods.