|Dailey Jr, Oliver|
Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 11, 2004
Publication Date: November 3, 2004
Citation: Dailey, Jr.,O.D. 2004. Volatilization of Alachlor from Polymeric Formulations. Journal of Agricultural and Food Chemistry. 52(22):6742-6746. Interpretive Summary: Pesticides may be dispersed throughout the environment by several means, including groundwater contamination, surface water contamination, and volatilization with subsequent transportation in the atmosphere. Volatilization is not just a source of pesticide loss but can be a contributor to environmental pollution of surface and groundwater, as a consequence of precipitation. In earlier research, a number of herbicides were encapsulated within several different polymers, providing polymeric formulations. In the studies described in this paper, three polymeric formulations of the herbicide alachlor, which had been found to be the most effective in greenhouse studies, were evaluated in laboratory volatility studies. In direct comparison with pure alachlor and a commercial formulation of alachlor, the three polymeric formulations reduced volatilization of the herbicide. A formulation prepared using the polymer cellulose acetate butyrate gave the best results. This research benefits formulation chemists, agronomists, environmentalists, and the agrochemical industry in that it identifies polymers suitable for formulation of alachlor and other volatile pesticides in order to reduce volatilization upon application in the field.
Technical Abstract: Pesticides may be dispersed throughout the environment by several means, including groundwater contamination, surface water contamination, and volatilization with subsequent atmospheric transport. In earlier research primarily directed at reducing the potential for groundwater contamination, a number of herbicides were microencapsulated within several different polymers. These polymeric formulations were evaluated for efficacy in the greenhouse. In these studies, three polymeric alachlor formulations which were the most effective in greenhouse studies were evaluated in laboratory volatility studies using pure alachlor and a commercial formulation (Lasso 4EC) for comparison purposes. In a given experiment, technical alachlor, Lasso 4EC, and two polymeric formulations were applied to soil and evaluated in a contained system under 53% humidity with a fixed flow rate. Evolved alachlor was collected in ethylene glycol, recovered with C18 solid phase extraction cartridges, and analyzed by reverse-phase high performance thin layer chromatography with densitometry. Duration of the studies ranged from 32 to 39 days. In studies in which all the formulations were uniformly incorporated in the soil, total alachlor volatilization from the polymeric microcapsules was consistently lower than that from the alachlor and Lasso 4EC formulations. In studies in which the polymeric formulations were sprinkled on the surface of the soil, microcapsules prepared with the polymer cellulose acetate butyrate released the smallest quantity of volatilized alachlor.