Concentrations, particle-size distributions, and dry deposition fluxes of aerosol trace elements over the Antarctic Peninsula in austral summer

Size-segregated particulate air samples were collected during the austral summer of 2016-2017 at Palmer Station on Anvers Island, western Antarctic Peninsula, to characterize trace elements in aerosols. Trace elements in aerosol samples - including Al, P, Ca, Ti, V, Mn, Ni, Cu, Zn, Ce, and Pb - were determined by total digestion and a sector field inductively coupled plasma mass spectrometer (SF-ICP-MS). The crustal enrichment factors (EFcrust) and k-means clustering results of particle-size distributions show that these elements are derived primarily from three sources: (1) regional crustal emissions, including possible resuspension of soils containing biogenic P, (2) long-range transport, and (3) sea salt. Elements derived from crustal sources (Al, P, Ti, V, Mn, Ce) with EFcrust < 10 were dominated by the coarse-mode particles (> 1.8 mu m) and peaked around 4.4 pm in diameter, reflecting the regional contributions. Non-crustal elements (Ca, Ni, Cu, Zn, Pb) showed EFcrust > 10. Aerosol Pb was primarily dominated by fine-mode particles, peaking at 0.14-0.25 mu m, and likely was impacted by air masses from southern South America based on air mass back trajectories. However, Ni, Cu, and Zn were not detectable in most size fractions and did not present clear size patterns. Sea-salt elements (Ca, Na+, K+) showed a single-mode distribution and peaked at 2.5-4.4 mu m. The estimated dry deposition fluxes of mineral dust for the austral summer, based on the particle-size distributions of Al measured at Palmer Station, ranged from 0.65 to 28 mg m(-2) yr(-1) with a mean of 5.5 +/- 5.0 mg m(-2) yr(-1). The estimated dry deposition fluxes of the target trace elements in this study were lower than most fluxes reported previously for coastal Antarctica and suggest that atmospheric input of trace elements through dry deposition processes may play a minor role in determining trace element concentrations in surface seawater over the continental shelf of the western Antarctic Peninsula.