Abstract
Health-effects of nanoparticles in humans are little understood. Pre-shift and post-shift FeNO, spirometry and markers in exhaled breath condensate (EBC) were measured in 20 workers exposed to TiO2 aerosol and 17 controls.
Particle number size distributions were monitored by aerosol spectrometers SMPS and APS, covering the overall size range 15 nm-10 microm. Simultaneously, the spatial distributions of total particle number and mass concentrations were determined using a particle number concentration monitor (P-TRAK) and a monitor of particle mass concentrations (DustTRAK DRX).
Malondialdehyde (MDA), 4-hydroxy-trans-nonenale (HNE), 4-hydroxy-trans-hexenale (HHE), 8-isoProstaglandin F2alpha (8-isoprostane), 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), hydroxymethyl uracil (HMeU), o-tyrosine (o-Tyr), 3-chloro-tyrosine (3-Cl-Tyr), nitrotyrosine (NO-Tyr), C6-C13, and leukotrienes (LTs) were analyzed after solid-phase extraction by LC-ESI-MS/MS. Total aerosol concentrations in the production plant varied greatly in both space and time; number concentrations 1x104-2x105 particles/cm3 and mass concentrations 0.1-30mg/m3.
In the workshops, 90% of the particles were smaller than 100 nm in diameter and particle concentrations were 10x higher than in the control room. All pre-shift EBC markers, excluding LT D4, were increased in the workers.
Markers of lipid oxidation were significantly elevated (p<0.01): MDA, HNE, HHE, and 8-isoprostane. All markers of C6-C13 oxidation were elevated (p<0.01).
Markers of oxidation of nucleic acids and proteins were increased (p<0.001): 8-OHdG, 8-OHG, HMeU, 3-Cl-Tyr; also NO-Tyr, o-Tyr and LT B4, C4 and E4 were elevated. Solely LTB4 was higher in smoking workers.
This first in-vivo study in workers suggests adverse effects of chronic exposure to TiO2 aerosol even in nano-sized fractions.