Biological and nonbiological modifications of organophosphorus compounds

The general types of biological reaction that are most prominent in the modification of organophosphorus compounds involve the mixed-function oxidases, hydrolases, or transferases. In certain cases, more than one of these reactions may be involved at the same site on the pesticide molecule. Examples of various organophosphorus pesticides that are altered by oxidation, hydrolysis, alkyl- or aryl-group transfer, reduction, and conjugation are discussed. The increase or decrease in toxicity of a pesticide that can result from biological modification is emphasized.Non-biological transformations of organophosphorus compounds involve the effect ou the compounds of such factors as light, air, temperature, and solvent. These factors are discussed with special emphasis on desulfuration, rearrangement, and oxidation.