Assessment of in vitro inhalation bioaccessibility of airborne particle-bound potentially toxic elements collected using quartz and PTFE filter

Atmospheric particulate matters (TSP and PM2.5) were sampled using quartz fiber filters and polytetrafluoroethylene (PTFE) filters, respectively. Particles deposited on the filters were characterized by a scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and an attenuated total reflection FT-IR spectroscopy (ATR-FT-IR). The in vitro inhalation bioaccessibility of TSP- and PM2.5-bound potentially toxic elements (PTEs) on the quartz fiber and PTFE filters with different physico-chemical properties were extracted by four kinds of in vitro inhalation bioaccessibility procedures. SEM-EDX spectra under different magnifications show the heterogeneous distribution and agglomeration of PM2.5 collected on the quartz fiber filter and PTFE filter. Results of ATR-FT-IR show different surface functional groups of PM2.5 deposited on quartz fiber and PTFE filters. 24 h was the optimal interval time for the analyses of in vitro inhalation bioaccessibility of TSP-bound PTEs. The in vitro inhalation bioaccessibility of TSP- and PM2.5-bound PTEs varied greatly among four in vitro inhalation bioaccessibility procedures. The in vitro inhalation bioaccessibility of TSP- and PM2.5-bound PTEs didn't show strong dependence on the quartz fiber filters and PTFE filters with different properties. The in vitro inhalation bioaccessibility procedures have greater influence on the in vitro inhalation bioaccessibility of particle-bound PTEs than the kinds of the sampling filters.