A variety of long-chain alkylamines (NR1R2R3, where Rn=H, CH3, C14H29, C16H33 OR C18H37) have been photooxidized in pure water and seawater (λ>290 nm). Half-lives of these amines in the two aqueous systems ranged from 25-95 min and 175-300 min, respectively, depending on the number and molecular weight of alkyl substituents