Pollution from the 2014–15 Bárðarbunga eruption monitored by snow cores from the Vatnajökull glacier, Iceland

• Published in: Journal of Volcanology and Geothermal Research
• Main Authors: Galeczka, Iwona, Eiriksdottir, Eydis Salome, Pálsson, Finnur, Oelkers, Eric, Lutz, Stefanie, Benning, Liane G., Stefánsson, Andri, Kjartansdóttir, Ríkey, Gunnarsson-Robin, Jóhann, Ono, Shuhei, Ólafsdóttir, Rósa, Jónasdóttir, Elín Björk, Gíslason, Sigurður Reynir
• Other Authors: Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier BV 2017
• Subjects: Eldgos; Gosefni; Loftmengun; Snjóalög; Vatnajökull; Bárðarbunga; Langjökull; glacier; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/2004; https://doi.org/10.1016/j.jvolgeores.2017.10.006

Post-print (lokagerð höfundar) The chemical composition of Icelandic rain and snow is dominated by marine aerosols, however human and volcanic activity can also affect these compositions. The six month long 2014–15 Bárðarbunga volcanic eruption was the largest in Iceland for more than 200 years and it released into the atmosphere an average of 60 kt/day SO2, 30 kt/day CO2, 500 t/day HCl and 280 t/day HF. To study the effect of this eruption on the winter precipitation, snow cores were collected from the Vatnajökull glacier and the highlands northeast of the glacier. In addition to 29 bulk snow cores from that precipitated from September 2014 until March 2015, two cores were sampled in 21 and 44 increments to quantify the spatial and time evolution of the chemical composition of the snow. The pH and chemical compositions of melted snow samples indicate that snow has been affected by the volcanic gases emitted during the Bárðarbunga eruption. The pH of the melted bulk snow cores ranged from 4.41 to 5.64 with an average value of 5.01. This is four times greater H+ activity than pure water saturated with the atmospheric CO2. The highest concentrations of volatiles in the snow cores were found close to the eruption site as predicted from CALPUFF SO2 gas dispersion quality model. The anion concentrations (SO4, Cl, and F) were higher and the pH was lower compared to equivalent snow samples collected during 1997–2006 from the unpolluted Icelandic Langjökull glacier. Higher SO4 and Cl concentrations in the snow compared with the unpolluted rainwater of marine origin confirm the addition of a non–seawater SO4 and Cl. The δ34S isotopic composition confirms that the sulphur addition is of volcanic aerosol origin. The chemical evolution of the snow with depth reflects changes in the lava effusion and gas emission rates. Those rates were the highest at the early stage of the eruption. Snow that fell during that time, represented by samples from the deepest part of the snow cores, had the lowest pH and highest concentrations ...