Correlation of in Vivo Relative Bioavailability to in Vitro Bioaccessibility for Arsenic in Household Dust from China and Its Implication for Human Exposure Assessment

Incidental ingestion of household dust is an important arsenic (As) exposure pathway for children. However, compared to soils, assessment of As relative bioavailability (RBA) in household dust is limited. In this study, As-RBA in 12 household dust samples (7-38 mg kg(-1)) was measured using an in vivo mouse model and compared to As bioaccessibility determined using 4 assays [Solubility Bioaccessibility Research Consortium method (SBRC), in vitro gastrointestinal method (IVG), Deutsches Institut fur Normunge V. method (DIN), and physiologically based extraction test (PBET)]. Arsenic RBA ranged from 21.8 +/- 1.6 to 85.6 +/- 7.2% with samples containing low Fe and high total organic carbon content having higher As-RBA. Strong in vivo-in vitro correlations (IVIVC) were found between As-RBA and As bioaccessibility for SBRC and DIN (r(2) = 0.63-0.85), but weaker ones were obtained for IVG and PBET (r(2) = 0.29-0.55). The developed IVIVC for SBRC and DIN were used to calculate As-RBA based on As bioaccessibility for an additional 12 household dust samples. Although As bioaccessibility differed significantly (up to 7.7-fold) based on in vitro methods, predicted As-RBA was less variable (up to 3.0-fold) when calculated using As bioaccessibility data and the corresponding IVIVC. Our data suggested that both SBRC and DIN had potential to assess As bioavailability in household dust samples; however, additional research is needed.