Case Study in Environmental Chemistry....

Authors: Sarunya Hengpraprom and Cindy Lee, Environmental Engineering and Science, Clemson University.

Abstract : This case study considers the rate at which exposure to sunlight can transform a pesticide known as terbufos. Transformation of a contaminant by photolysis will change its behavior in a given situation. In some cases, a product of photolysis is just as toxic or more toxic than the parent compound. In other cases, the products of photolysis are rendered nontoxic and the transformation can be considered beneficial. The experiment described in this case study produced some of the first basic kinetics data available to evaluate the importance of photolysis as a process to remove terbufos from the environment. For more detailed information about this research, see Lee, C. M.; Anderson, B.; and Elzerman, A. W. 1999. Photochemical oxidation of terbufos. Environmental Toxicology and Chemistry. 18(7):1349-1353.

Basic Manufacture and Formulation

Terbufos is manufactured by American Cyanamid of Princeton, NJ, and brought to the market under the trade names of AC 92100, Aragran, Contraven, Counter, and Plydox (3, 8). The most commonly available formulation is granular which consists of 15% active ingredient (terbufos) bound to an inert, clay-like matrix (3). The structures of terbufos and its metabolite products are shown in Figure 1.