Persistence and fate of deltamethrin sprayed on a pond

When sprayed on a pond in Prince Edward Island, Canada, deltamethrin disappeared quickly from water with a half-life of about one hour. Major routes of degradation and dissipation were chemical and photochemical conversion to inactive deltamethrin stereoisomers, and hydrolysis with subsequent oxidation of products. No deltamethrin stereoisomer residues or any of the four major degradation products sought were found 11 days post-spray. Laboratory analyses of the volatilization of deltamethrin formulations from sprayed water as opposed to subsurface-injected water indicated that volatilization from the surface microlayer was a rapid process that could be the major route of dissipation.