Bringing Organophosphate Ester Tris(2,4-di- tert -butylphenyl) Phosphate to the Forefront: A Hidden Threat to the Environment

Tris(2,4-di- tert -butylphenyl) phosphite (AO168) is a widely utilized organophosphite antioxidant in the field of plastics. Throughout the production and usage processes, AO168 can undergo oxidation and convert into tris(2,4-di- tert -butylphenyl) phosphate (AO168═O), which has been identified as one of the novel organophosphate esters (OPEs). AO168═O is now extensively present in the environment, with concentrations generally exceeding those of traditional OPEs such as triphenyl phosphate and tri(2-chloroisopropyl) phosphate. Consequently, AO168═O has emerged as a significant concern that is receiving attention from the scientific community. However, there exists some controversy regarding the formation mechanisms and potential risks of AO168═O. This Review provides a comprehensive overview for the first time of the environmental occurrence, formation pathways, toxicities, and risks linked to AO168═O, aiming to assist researchers and policymakers in obtaining an unbiased description of its potential impacts on both the environment and human health. Given numerous unresolved aspects surrounding AO168═O along with its wide occurrence, greater attention should be devoted to this emerging contaminant.