Fate and decontamination of Novichok agent A232 on environmental and urban matrices

Novichoks are highly toxic chemical warfare agents (CWAs), which gained significant attention after being used in the assassination attempt of Sergei Skripal (2018, Salisbury). Since then, only a limited number of experimental studies on Novichoks were conducted with focus on their physicochemical properties, toxicology and pharmacology. Their stability on various matrices has received even minor consideration. Herein, we present a comprehensive study on the fate of A232, a prominent Novichok agent, on a variety of previously unexamined environmental and urban matrices, using solid and solution state ³¹P NMR techniques. The matrices studied included limestone soil, desert soil, silicate sand, asphalt, fresh and old concrete and sawdust, all in dry and wet forms. A232 was found to be highly persistent on most matrices, with degradation being very slow or nonexistent. Once degradation occurred, its products stemmed from either a PN bond or a PF bond cleavage or double hydrolysis of both leaving groups, depending on the matrix. The results indicate that A232 poses significant, long-term threat to the environment across a diverse range of realistic scenarios. Importantly, A232 adsorbed on solid support was rapidly and completely hydrolyzed to a nontoxic product once treated with only a few equivalents of NaOH.