Identification of Unusual Antioxidants in the Natural and Built Environments

Hindered phenolic antioxidants are common industrial chemicals that are added to polymers of all sorts and even to food. For example, on the order of 10⁷ kg of 2,6-di-tert-butyl-4-methylphenol (also known as BHT) is used in the United States every year. Despite their widespread use, the environmental fates of most of these compounds have not been well-investigated. The first step in such an investigation is the identification of those antioxidants that are present in environmental sources. This paper reports on the identification of two previously unsuspected antioxidants, Irganox 1076 and Irganox 1135. The latter is particularly abundant in a set of children's car seats we have previously investigated for flame retardants. We also demonstrate that both of these compounds degrade to 2,6-di-tert-butyl-p-benzoquinone and that this compound is very abundant in atmospheric particles collected in Chicago. We suggest that this benzoquinone is likely to be environmentally significant and deserves further attention.