Occurrence of synthetic phenolic antioxidants and transformation products in urban and rural indoor dust

Abstract In this study, seven synthetic phenolic antioxidant (SPA) analogues were positively found in urban and rural indoor dust samples collected from Shandong province in China, among which the novel 2,4,6-tri- tert -butylphenol (AO 246), 2,6-di- tert -butyl-4-sec-butylphenol (DTBSBP), 2,4-di- tert -butylphenol (DBP) and 4,4'-butylidenebis (2-(1,1-dimethylethyl)-5- methyl-phenol) (AO 44B25) analogues accounted for 29% of total SPA concentrations (∑SPAs). Urban dust showed significantly higher ∑SPA levels (range: 1.56e3 - 2.03e4 ng/g) compared with those in rural indoor dust (668–4.39e3 ng/g, p  97%), with individual residue level in the same order: 2,6-di- tert -butyl-1,4-benzoquinone (BHT-Q) > 2,6-di-tert-butyl-4-hydroxy- 4-methyl-2,5-cyclo-hexadienone (BHT-quinol) > 3,5-di- tert -butyl-4-hydroxybenzal-dehyde (BHT-CHO). Geometric mean values of total TP concentrations were 555 ng/g and 131 ng/g for urban and rural indoor dust samples, respectively. A preliminary estimated daily intake calculation at dust ingestion scenario suggested additional concerns might be paid to simultaneous exposure of several SPA analogues and TPs besides current focus on BHT exposure risks.