The Eyjafjallajökull eruption has been occurring since March 2010. In April, the eruption had 2 distinct stages: first was between 14/04 and 18/04 during which the large ash cloud was formed and explosive mixing between the glacial lake and the lava occurred. The second phase was characterised by a less explosive plume. This second phase is still continuing and intermittently the plume has passed over the UK at varying altitudes.

Mercury

Volcanoes are a major natural source for mercury and it can be found in the gas phase and associated with volcanic ash. The graph below shows the most recent 5 days of mercury measurements. This data is updated daily.

Normal air concentrations at remote UK sites are between 1.4 -1.5 ng/m3. Higher concentrations can be seen if air has passed over a coal-burning power station, a crematorium, an industrial source of mercury or a volcano before reaching the site. If the plume from Eyjafjallajökull reached the ground we would expect to see a significant increase in concentration. When elevated mercury levels are observed, to verify the origin of the mercury links to the source, e.g. the volcano, would then need to be made by following the path of the air prior to reaching the measurement site. Even at concentrations several times larger than the norm, elemental mercury in air poses no threat to human health.

[Concentration of elemental mercury in air (ng/m3 = billionths of a gram per cubic metre).]

Fluoride

Other chemicals emitted by volcanoes include fluoride and sulphate. As part of the Defra UKEAP monitoring network, of which Auchencorth is a component site, monitoring of the rain chemistry has been increased to check for any UK deposition from Eyjafjallajökull. The graph below shows fluoride levels in rain (both weekly average and daily sampling in April) at Auchencorth during 2010. In April 2010 there was no evidence of excess fluoride or sulphate in the rain, which supports the other evidence that there was not a significant deposition from Eyjafjallajökull. The two slightly higher fluoride concentrations were associated with rain which had high levels of all ions. Monitoring of rain chemistry is on-going and results will be updated as the measurements are made.

For more information regarding these and other Auchencorth measurements please use the contact form

See more Auchencorth live data.

See other CEH responses to the volcano.

CEH measures many atmospheric chemicals at its EMEP superersite Auchencorth Moss, 15 miles south of Edinburgh in the Scottish Borders. Of interest with respect to the volcano is the measurement of hourly mercury concentrations and fluoride. [Photo of ash plume: NASA/GSFC/Jeff Schmaltz/ MODIS Land Rapid Response Team]