A New Method for the Assessment of the Oxidative Potential of Both Water-Soluble and Insoluble PM

Abstract

Water-soluble and insoluble fractions of airborne particulate matter (PM) exhibit different toxicological potentials and peculiar mechanisms of action in biological systems. However, most of the research on the oxidative potential (OP) of PM is focused exclusively on its water-soluble fraction, since experimental criticisms were encountered for detaching the whole PM (soluble and insoluble species) from field filters. However, to estimate the actual potential effects of PM on human health, it is essential to assess the OP of both its water-soluble and insoluble fractions. In this study, to estimate the total OP (TOP), an efficient method for the detachment of intact PM10 from field filters by using an electrical toothbrush was applied to 20 PM10 filters in order to obtain PM10 water suspensions to be used for the DCFH, AA and DTT oxidative potential assays (OPDCFH, OPAA and OPDTT). The contribution of the insoluble PM10 to the TOP was evaluated by comparing the TOP values to those obtained by applying the three OP assays to the water-soluble fraction of 20 equivalent PM10 filters. The OP of the insoluble fraction (IOP) was calculated as the difference between the TOP and the WSOP. Moreover, each PM10 sample was analyzed for the water-soluble and insoluble fractions of 10 elements (Al, Cr, Cs, Cu, Fe, Li, Ni, Rb, Sb, Sn) identified as primary elemental tracers of the main emission sources in the study area. A principal component analysis (PCA) was performed on the data obtained to identify the predominant sources for the determination of TOP, WSOP, and IOP. Results showed that water-soluble PM10 released by traffic, steel plant, and biomass burning is mainly responsible for the generation of the TOP as well as of the WSOP. This evidence gave strength to the reliability of the results from OP assays performed only on the water-soluble fraction of PM. Lastly, the IOPDCFH and IOPDTT were found to be principally determined by insoluble PM10 from mineral dust.

Experimental factors influencing the bioaccessibility and the oxidative potential of transition metals from welding fumes

“…The residual mineral particles play a non-negligible role in the OP DTT of the insoluble phase. 44 In addition, these particles may have long-term toxicity due to their prolonged persistence in biological tissues. 85 The toxicity of these particles can be attributed to their surface properties, as indicated by Fang et al (2017).…”

“…40,41 However, several studies suggest that the immune response in the lung aer exposure to airborne particles is related to the content of both solubilized 2,3,27,42 and insoluble fractions. 43,44 The solubility of metals in physiological uids is determined by cell-free in vitro methods that approximate physiological properties and biochemical conditions. 20,38,45,46 The biological response of particle-bound species is largely inuenced by the extraction protocol.…”

Oxidative potential of fine particulate matter emitted from traditional and improved biomass cookstoves

“…Using the corrected WS-and total-DTT activities and following the procedure of Fang et al, 42 ). 41,[43][44][45] We note that this approach assumes WS-and WI-DTT activities are additive and does not account for potential (synergistic or antagonistic) interactions between the WS and WI components, which remain unknown and warrant future investigation. For intrinsic (potency) DTT activity, the corrected total-DTT activities were normalized by the PM 2.5 mass on the lter punch (OP Total-DTT mass , pmol min −1 mg −1 ).…”

Oxidative potential of the inhalation bioaccessible fraction of PM10 and bioaccessible concentrations of polycyclic aromatic hydrocarbons and metal(oid)s in PM10

“…OP DTT and OP AA have been extensively assessed after PM 10 extraction by vortex/rotating/shaking (Calas et al 2017 ; Massimi et al 2020 ; Frezzini et al 2022a , 2022b ; Altuwayjiri et al 2022 ; Fang et al 2023 ) or ultrasound (Janssen et al 2014 ; Perrone et al 2016 ; Chirizzi et al 2017 ; Rezaei et al 2018 ; Patel and Rastogi 2018 ; Pietrogrande et al 2018a , b ; Perrone et al 2019 ; Lionetto et al 2019 ; Pietrogrande et al 2021 ; Lionetto et al 2021 ; Wang et al 2018 ; Pietrogrande et al 2022a , b ; Giannossa et al 2022 ; Frezzini et al 2022b Farahani et al 2022 ; Molina et al 2023 ; Guascito et al 2023 ; Clemente et al 2023 ) assisted using ultrapure water, methanol, or buffer as solvents 1 ). However, ultrapure water, methanol, or buffers differ in several characteristics (pH, ionic strength, or the deficiency of complexing ligands) from lung fluids (Calas et al 2017 ).…”

“…However, ultrapure water, methanol, or buffers differ in several characteristics (pH, ionic strength, or the deficiency of complexing ligands) from lung fluids (Calas et al 2017 ). On the other hand, the use of ultrasound has been shown to induce the formation of ROS in the solution, enhancing the solubilization of PM insoluble species and causing an overestimation of the OP due to the high efficiency of the extraction assisted by ultrasound energy (Massimi et al 2020 ; Frezzini et al 2022a ).…”