Synthetic
antioxidants represent a complex group of additive chemicals
broadly used in consumer products. While traditional antioxidants
such as 2,6-di-tert-butyl-4-methylphenol (BHT) have
been well studied, a variety of “novel” antioxidants
have emerged with extensive applications but received much less attention.
Our study aimed to explore a suite of 34 emerging antioxidants in
house dust from four different regions, including Guangzhou (China),
Adelaide (Australia), Carbondale (Illinois), and Hanoi (Vietnam).
The results revealed broad occurrence of several rarely investigated
chemicals in house dust across regions, including triethylene glycol
bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate
(AO245), 2,6-di-tert-butyl-4-(dimethylamino)methylphenol
(AO4703), 2,2′-thiene-2,5-diylbis(5-tert-butyl-1,3-benzoxazole)
(BBOT), 1,3-diphenylguanidine (DPG), 2,4-bis(1,1-dimethylethyl)phenol
(2,4DtBP), and 2,6-bis(1,1-dimethylethyl)phenol (2,6DtBP). In particular,
DPG exhibited a median concentration of 5030–11 400
ng/g in house dust from the studied regions except for Hanoi (305
ng/g), generally 1 order of magnitude greater than that of BHT (890–1060
ng/g) and dominating the compositional profiles of antioxidants. Estimated
intake of target antioxidants by toddlers via dust ingestion, even
under the high exposure scenario, was determined to be 2–4
orders of magnitude lower than the reference doses of selected antioxidants.
However, potential risks from long-term exposure to a cocktail of
antioxidants under environmentally relevant concentrations merit further
investigations due to insufficient knowledge on the sources, fate,
and toxicokinetics of these chemicals to date.