Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes

Speciation of inorganic trivalent arsenicals (iAs^III), inorganic pentavalent arsenicals (iAs^V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM_2.5 was investigated. Inorganic As, especially iAs^V, was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM_2.5. Reduction of iAs^V to iAs^III occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption.