Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 10/5/2001
Publication Date: N/A
Technical Abstract: Adsorption of two acidic herbicides, bentazone and dicamba, was studied to assess their efficiency for immobilising those herbicides present in the soil. Adsorption of both herbicides increases with the size of the saturation cation, suggesting hydrophobic interactions as the main responsible for sorption. Accordingly, adsorption was greater for organoclays with high basal spacing, OC content and organocation saturatio close to CEC and lower for dicamba with larger water solubility. The treatment of an artifically contaminated soil with the two organoclays, displaying highest herbicide adsorption, showed that the availability (CaCl2 0.01M extractability) of the herbicides decreased dramatically, from 80% up to 2% for bentazone and 12% for dicamba. Pesticide sorbed on the organoclay, and thus immobilised, was partially extractable with methanol/CaCl2 solution suggesting its potential bioavailability. These results suggest the possible use of organoclays as immobilising agents for clean up in soils contaminated with acidic herbicides.