Impacts of volcanic ash originating from the April 2010 eruption in Eyjafjallajökull (Iceland) on the natural resources of Scotland

Executive Summary The fall out of volcanic ash from the eruption of the Icelandic volcano Eyjafjallajökull caused significant travel disruption and raised concerns about the potential impacts on Scottish natural resources. This report provides an evaluation of these potential impacts on 3 main resource areas: (i) pastures and livestock; (ii) soils and (iii) surface water. This is based on current scientific opinion as well as post-eruption data collected from long-term monitoring sites. This report has been prepared as part of research funded by the Scottish Government. Volcanic eruptions result in substantial emissions of gases and ash particles. The varying characteristics of ash between volcanoes and individual eruptions and the consequent transport patterns increase uncertainty of predicting the impact of ash fall on pasture, soils and waters across Scotland. According to the US Energy Information Administration, global human activity contributed 29,195 million tonnes of CO2 to the air in 2006. Thus the Eyjafjallajökull eruption, although not insignificant at a maximum 30000 tonnes day-1 will not make a substantial addition to global anthropogenic atmospheric CO2 emission. The majority of the ash from the recent eruption appears to be fine grained glass particles, which can be dispersed widely. The main risks are to livestock through fluoride ingestion from volcanic ash on pasture. Initial indications are that the volcanic ash layer deposited in Scotland was thin (< 5 mm), and effects on pasture and soils are negligible. It is also clear that not enough ash was deposited to have a negative effect on water quality. Initial data collected by the Macaulay Land Use Research Institute indicates that ash was present in Scottish rainfall and snow samples collected following the eruption. However, there were little measurable effects in surface waters in this instance compared to pre-eruption data. Measurable effects may have been associated with increased fluoride concentrations derived from ash that has fallen directly onto water surfaces and acidification episodes caused by increasing sulphate deposition in rainfall and snow that is then rapidly transported to rivers and lakes. Higher altitude and acid prone areas of Scotland are potentially more sensitive to increased inputs from the volcanic eruption leading to surface waters experiencing more acidic conditions than otherwise expected during snowmelt or high rainfall periods. Thus seasonality of deposition can have a major bearing on the associated risk of negative impacts, such as impacts that coincide with when freshwater fish, such as trout and salmon are …