George Bizzigotti

CCB organic seminar presentation by Dr. George Bizzigotti, Noblis. 

Talk title: "Chemical Warfare Agents - Problems Related to Sea Disposal and Decontamination"

Abstract:

From 1918 until 1970, dumping of obsolete and leaking chemical weapons into the ocean was an accepted practice. Dr. Bizzigotti will outline some of the history of US disposal of chemical weapons in the ocean, the fate of those weapons in the marine environment, and recent work on the dissolution of the chemical agent sulfur mustard. The US disposed of a total of approximately 30,000 tons of chemical agent in several locations off its coasts, and the worldwide total for sea disposal is not known precisely, but is estimated to be on the order of several hundred thousand tons. Our group at Noblis pioneered assessments of the risk posed by underwater chemical weapons, recently reviewed physical and chemical parameters required for evaluation of the fate, transport, and environmental impacts of chemical warfare agents in marine environments.
 

Very recently, our group has focused on the behavior of the chemical warfare agent sulfur mustard, which reacts relatively rapidly with water when dissolved, yet paradoxically can persist underwater for decades. To help understand the interplay of dissolution and aqueous reaction, we have developed a mathematical model that combines the rates of the two processes. We have also developed modifications to the model to allow for the effects of surfactants on dissolution and reaction rates, and examined the sensitivity to various parameters. In general, the rate at which sulfur mustard disappears from the system is quite sensitive to parameters that affect dissolution (initial droplet size, specific dissolution rate at the interface, surfactant concentration, partition coefficients), but much less sensitive to reaction rates in the aqueous and micellar pseudophases. This model also has implications for future research on the decontamination of sulfur mustard.