Volcanic ash cloud – the latest news from SEPA - update 2

  17 April 2010

The Scottish Environment Protection Agency (SEPA) is monitoring the situation regarding the volcanic ash cloud currently affecting the UK and its possible impact on Scotland’s environment.

SEPA’s Director of Science and Strategy, Professor James Curran, said:

The greatest environmental concern from volcanic ash, and the most significant risk to grazing livestock, would be fluoride content in ash deposits. Information from SEPA’s analysis of Scottish dust samples, and from similar analysis in Norway, indicates low levels of fluoride in the current Icelandic ash plume.

“We think, on the basis of the expected deposition patterns and the nature of the ash, that there is a minimal risk to the environment.”

Ongoing monitoring

Continuous environment monitoring will be ongoing over the weekend and beyond, using information about from a wide network of existing environmental monitoring sites across Scotland. 

SEPA and the Met Office will also attempt to collect rainwater samples over the weekend of 17 to 18 April.  These will be analysed by SEPA for pH and soluble fluoride.

Radiation measurements taken across the UK and Europe indicate there is no evidence that the volcanic ash contains radioactive materials of any significance.

The Scottish Air Quality Database contains the most up-to-date continuous ambient monitoring information across Scotland. Members of the public can access this information at www.scottishairquality.co.uk. All concentrations have remained low at all monitoring sites across Scotland.

Latest results from SEPA’s dust analysis

SEPA analysed three dust samples collected in Lerwick, Aberdeen and East Kilbride.

Lerwick sample which was collected from a radiation monitor on the roof of the Met Office on to a paper tissue.

Initially a small portion of the Lerwick sample was placed on a microscope slide for examination.  The sample was dark grey, black in appearance.  Under microscope there were aggregrates of dark grey, black particles possibly opaque material covered in a dark deposit.  This was interspersed with regular shaped angular particles of glassy appearance.  The particles ranged in size from 15 x 20 µm to 70 x 85 µm.

The Aberdeen sample was also examined and was found to contain angular particles of glassy appearance and were approximately 60 x 70 µm in size.

Further analysis conducted by the Macaulay Institute showed broadly uniformed sized (approximately 20 µm) particles of angular shape some exhibiting striations and others conchoidal (smooth curved surfaces) fractures (typical of quartz and glass).

Most particles showed similar composition consisting of silicon, oxygen, aluminium, sodium, calcium, magnesium, potassium, iron and chloride.  There was no evidence of high concentrations of fluorine in this sample.

Based on the morphology of the particles (angular with conchoidal fracture faces) and the fairly uniform elemental composition of the particles it is likely that the sample is of volcanic origin.

The sample collected at East Kilbride was examined by microscopy in East Kilbride and also found to contain glassy, angular particles which were identified as ‘new silica’ ie sharp, bright and clear as opposed to smooth and opaque.  This is typical of volcanic material.

Notes to editors

Environmental monitoring sites include 75 sites air quality monitoring sites (results available live on www.scottishairquality.co.uk). SEPA also uses data from other local air quality monitoring sites across Scotland.

SEPA also runs 25 radioactivity monitoring sites across the country. Some locations also have dust filters that are being collected for analysis not only for their normal purpose but also to provide additional samples for volcanic dust analysis.

SEPA’s field chemistry team is also collecting further additional dust samples from across Scotland for analysis.

Some rainfall is predicted in north west Scotland over the weekend. SEPA and the Met Office will attempt to collect rainwater samples for analysis by SEPA for pH and soluble fluoride.