Analysis of nano- and micro- particles in ice cores from polar and high altitude glaciers by spICP-TOFMS

Due to its small particle size, nanoparticle (NPs) and and microparticles (μPs) could reside in the air for a long time affecting human health and the environment. Understanding of its sources and dynamics in the atmosphere remains a complex challenge since direct observations are limited. Ice cores drilled from glaciers around the world contain records of atmospheric composition over time. Single particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (spICP-TOFMS) is uniquely capable of quickly (in ~10 minutes) measuring the estimated mass equivalent size distribution, number concentration, and elemental chemical composition (up to 70 elements excluding O, H, N, F, and the noble gases) of more than 100,000 individual insoluble mineral NPs and μPs using <0.5 mL of melted ice. spICP-TOFMS allows us not only to consider the total mass concentrations of each element but also assess distribution of particles within each sample depending on elemental composition. Here, we present the results of spICP-TOFMS application for three sets of discrete samples: 1) Ice samples from the "horizontal ice core" from the Taylor Glacier (coastal East Antarctica) (44 – 9 kyrs BP). 2) Mt. Ortles (European Alps) ice core samples spanning from the pre-Roman period (780 BCE) to the modern era (1955 CE). 3) Snow and ice samples at the Upper Fremont glacier, WY, USA collected in 2024.

Study of 28 Taylor Glacier samples using spICP-TOFMS reveals changes in the concentration, size distribution, composition, and inferred mineralogy of individual particles during the last glacial-interglacial transition providing a first assessment of natural background variability of NPs and μPs in Antarctica. Samples from the Last Glacial Maximum (LGM, 18–29 kyr) tend to contain more sub-micron particles with higher fractions of Al, Mg, Na and Ca, and lower fractions of Si suggesting an additional input of material of a different elemental composition most likely due to varying mineralogical sources during the LGM compared to the Holocene. spICP-TOFMS analysis of samples from Mt. Ortles and Upper Fremont glacier were used to investigate anthropogenic particles. We observed enrichments for: Pb, Sb, Bi, Cu, Zn, Sn, Cr, Mo and Ni in modern samples. The percentage of Pb-containing particles increased by about a factor of ten in the most modern samples compared to the oldest sample. The total % mass due to Sn, Bi, and Pb were 26 to 97x higher in the modern samples than in the pre-Roman Mt. Ortles samples, consistent with those elements having significant contributions from anthropogenic sources. This study was supported by NSF Award 1744961.