UK: Volcanic Ash -- No Immediate Concerns for Animal Health.
April 16 2010 -- Significant deposits of volcanic ash are required in order to pose a risk to Livestock, the Scottish Environment Protection Agency (SEPA) has said.
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.
A spokesman for SEPA said environmental risks include water contamination. He said: "Newly fallen volcanic ash may result in short-term physical and chemical changes in water quality although the information that we have found indicates that historical eruptions have caused few water quality problems."
He added: "The most common effects are from the suspension of ash on uncovered water supplies such as reservoirs. This may result in a change in turbidity and acidity although this is generally short-lived (a few hours to days). Such impacts seem to be associated with significant ash falls e.g. greater than three millimetres. The main concern of fluorine poisoning is for livestock, which graze on ash-contaminated grass and feed, but significant deposits are usually required. Continuous monitoring of the situation is ongoing but the current available evidence suggests that there is a minimal risk to human health and the wider environment."
A sample of the ash which fell in Lerwick, Shetland has been collected and delivered to SEPA's laboratory in Aberdeen where it is currently being anaylsed.
No Immediate Concerns
Typical chemical composition of volcanic ash
Volcanoes emit a variety of gases including H2O, CO2, SO2, HCl, NH3, H2S, HF. These gases interact rapidly with the ash particles of a volcanic plume and especially atmospheric water to form acidic aerosols.
Volcanic ash may therefore contain potentially harmful substances in the form of water-soluble materials, mostly acids and salts, which cling to the particles of glass and crystals. The most common are sulphate, chloride, sodium, calcium, potassium, magnesium and fluoride. Other elements reported but in lower concentrations include metals such as zinc, cadmium and lead.
Finer ash is able to carry more soluble ions than coarser ash because of its larger surface area; fine ash and smaller-sized ash travel greater distances from an erupting volcano, typically extend over very wide areas than larger ash particles and may stay airborne for lengthy periods.
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|Publication:||Feedinfo News Service|
|Date:||Apr 16, 2010|
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