Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/16/2009
Publication Date: 6/15/2009
Citation: Trigo, C., Koskinen, W.C., Celis, R., Cornejo, J. 2009. Clay-based Formulations to Reduce the Environmental Impact of the Herbicide Terbuthylazine [abstract]. American Chemical Society. 77:104. Interpretive Summary:
Technical Abstract: Controlled release formulations of pesticides are receiving increasing attention as a way to reduce the environmental impact of pesticides after their application to agricultural soils. Natural and modified clay minerals have been proved to be efficient adsorbents for many pesticides and, accordingly, they have been proposed as supports in the designing of pesticide slow release formulations. In this work, we prepared clay-based formulations of the herbicide terbuthylazine by supporting the herbicide on Fe(III)-treated Wyoming montmorillonite (SW-Fe) and hexadecyltrimethylammonium (HDTMA)-treated Arizona montmorillonite (SA-HDTMA). Despite both SW-Fe and SA-HDTMA displayed very high affinity for terbuthylazine, only SA-HDTMA retained the herbicide in a reversible, bioavailable form. Interaction of terbuthylazine with SW-Fe resulted in scarce bioavailability of the herbicide, thus limiting the usefulness of the adsorbent as a support for the slow release of the herbicide. We discuss how the nature of the clay-pesticide interaction mechanism can condition the performance of clays as supports in controlled release formulations of pesticides.