Rapid assessment of the potential health hazard of ash from Kilauea Volcano, Hawai'i

Over the past 25 years, multidisciplinary research has tried to determine whether volcanic ash is a respiratory health hazard. The question first arose following the eruption of Mt. St. Helens, USA, in 1980, where the ash contained potentially-toxic crystalline silica. Medical and toxicological studies have given inconclusive results regarding the ability of ash to cause long-term diseases but it is now known that ash can trigger acute diseases like asthma. With ~ 9 % of the world's population living within 100 km of a historically active volcano, establishing whether ash can cause disease is an urgent priority and results have immediate impact on hazard management decisions. Following several months of precursory activity, Halema`uma`u crater on Hawai'i's Kilauea Volcano became active on 12 March 2008. The new gas vent became 'ash-laden' on 24 March and this represents the first lava to be erupted from Halema`uma`u since 1982. The 'Big Island' of Hawai'i is already affected by a plume of volcanic smog ('vog' / aerosol and gas) produced by Kilauea Volcano. Trade winds blow the vog to the southwest, along the island's Kona coast, affecting ~ 10,000 people. When trade winds are disrupted, the plume is blown to the east, potentially affecting tens of thousands of people. Hawai'i would be severely affected by substantial ash fall (which poses a different health risk from volcanic gas) and it is essential that we determine the health hazard of the ash as soon as possible. Medical studies to determine the health effects of volcanic ash may take years to complete. Rapid analysis of the potential health hazard can be carried out in hours, using mineralogical techniques to characterise the particle properties, providing results for hazard managers within days of population exposure. In particular, we can determine the grain size of ash particles / if they are too large to enter the lung, they cannot pose a respiratory health hazard. Conversely, if they are inhalable, hazard managers can mitigate the hazard by providing dust masks or even evacuating. Basaltic ash (such as that found on Hawai'i) is often coarse grained and, until recently, had been disregarded as a health hazard due to this and the lack of crystalline silica in its composition. However, in vigorous eruptions, basaltic ash can be fine enough to enter the lungs Basaltic ash is also iron rich. It is known that iron can generate free radicals which can be a factor in causing lung cancer and inflammation. Recently, Horwell (PI) found that basaltic ash can generate these radicals and, with this discovery, for the first time, basaltic ash was recognised as a potential health hazard. With this new information, it is crucial that the potential hazard of the Hawaiian ash is determined early in the eruption so that hazard managers can decide how to protect the exposed population. We will carry out two types of research: 1) Rapid response: A research assistant will set up a network of ash collection trays which will be maintained daily over 12 weeks. Once per week, the ash samples will be sent to the UK. The grain size of ash particles being emitted from Kilauea Volcano will be analysed every week to determine whether particles are small enough to enter the lungs. Results will be emailed to the Hawaiian Volcano Observatory (HVO) every week so that hazard managers can make immediate decisions regarding the current risk to the population. 2) Detailed analysis: Analysis of surface reactivity (iron-induced radical generation) and composition of samples will take place in the UK to determine the likely toxicity of particles. If the ash is found to be reactive, this will also pave the way for future toxicological studies to understand how the ash affects cells. The project will take 4 months (3 months fieldwork; 1 month laboratory work and write up). All results will be sent to HVO and will be written up for publication in an international volcanology journal.