Concentrations, Particle-Size Distributions, and Dry Deposition Fluxes of Aerosol Trace Elements over the Antarctic Peninsula

Abstract. Size-segregated particulate air samples were collected during the austral summer of 2016–2017 at Palmer Station on the Anvers Island off the west 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 sector field inductively coupled plasma mass spectrometer (SF-ICP-MS). The results show that these elements are derived primarily from three sources: (1) regional crustal emissions, (2) long-range transport, and (3) sea-salt aerosols. Elements dominated by a crustal source (Al, P, Ti, V, Mn, Ce) with EFcrust   1 μm) and peaked at 2.5–7.8 μm in diameter, reflecting the contributions of regional crustal sources. Non-crustal elements (Ca, Ni, Cu, Zn, Pb) showed EFcrust > 10. Aerosol Pb was accumulated primarily in fine-mode particles, peaking at 0.078–0.25 μm, and likely was impacted by air masses from South America based on air-mass back trajectories. However, Ni, Cu, and Zn were not detectable in most size fractions and didn't present clear size patterns. Sea-salt elements (Ca, Na, K) showed single mode distribution and peaked at 2.5–7.8 μm. The estimated dry deposition fluxes of 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 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 west Antarctic Peninsula.