Concentrations, spatial distribution, and human exposure of synthetic phenolic antioxidants in indoor dust from ten provinces in China

Synthetic phenolic antioxidants (SPAs) are widely used in diverse industries due to their exceptional antioxidant characteristics. However, human exposure to SPAs may cause health problems. In this study, 226 dust samples were collected from 10 provinces in China, and six SPAs (three parent SPAs and their three transformation products) were analyzed. The concentrations of ∑₆SPAs (the sum of six target compounds) ranged from 15.4 to 3210 ng/g (geometric mean (GM): 169 ng/g). The highest concentration of ∑₆SPAs was found in Sichuan Province (GM: 349 ng/g), which was approximately 4 times higher than that in Hubei Province (81.6 ng/g) (p < 0.05). The concentrations of butylated hydroxytoluene (BHT), 2,2′-methylene bis (4-methyl-6‑tert-butylphenol) (AO2246), 2,6-di‑tert‑butyl‑1,4-benzoquinone (BHT-Q), 2,6-di‑tert‑butyl‑4-(hydroxymethyl) phenol (BHT-OH), and ∑p-SPAs were substantially higher in dust from urban areas than rural areas (p < 0.05). AO2246 concentration in dust from homes (GM: 0.400 ng/g) was about 4 times higher than that in workplaces (0.116 ng/g) (p < 0.01). Significantly higher ∑p-SPAs concentrations were found in dust from homes (GM: 17.5 ng/g) than workplaces (11.4 ng/g) (p < 0.01). The estimated daily intakes (EDIs) of ∑₆SPAs exposed through dust ingestion were 0.582, 0.342, 0.197, 0.076, and 0.080 ng/kg bw/day in different age groups, and exposed through dermal contact was 0.358, 0.252, 0.174, 0.167, and 0.177 ng/kg bw/day. EDIs showed that the exposure risks of SPAs decreased with age. This is the first work to determine SPAs in dust from 10 provinces in China and investigate the spatial distribution of SPAs in those regions.