11. Health Effects From Volcanic Eruptions Kevin Friscia, Earth and Physical Sciences Department, Western Oregon University, Monmouth, Oregon, INTRODUCTION Geologic Processes Summary Discussion of Case Studies REFERENCES ABSTRACT Volcanic processes operated on Earth long before the onset of planetary life and biological evolution. Humans have long lived in the shadows of active volcanoes, with catastrophic deaths in proximal eruptive zones the most obvious hazard. Only in the past several decades have geoscientists begun monitoring the long term effects that volcanic emissions have on human health. Living near vents causes hazards associated with pyroclastic and lava flows, while farther away, fine atmospheric tephra pose other health problems. This study focuses on the long-term health effects from volcanic eruptions. Ejecta containing hot ash, gases and dust commonly result in inhalation, short-term respiratory stress, skin and ocular irritation. Inhalation of volcanic gases (e.g. SO 2, H 2 S, SO 3, H 2 SO 4 ) can lead to chronic respiratory disease and death. Understanding of the long- and short-term effects associated with volcanic eruptions is essential for developing public heath strategies and hazards mitigation plans in tectonically active regions. Both regional and global case studies are presented to demonstrate the relevance of medical geology with respect to applied practice. Health Connection My discussion is mainly based on long term effects of volcanic eruptions. Apart from thermal and physical injuries from an eruption, ejecta may also contain toxic elements that can cause long term damage (Weinstein 2005). Emissions from volcanic eruptions cause the most harmful effects, which include hot ash, gases and dust. Hot ash can cause irritation of the skin causing a rash from contact. Eye damage is cause by fine tephra particles that make contact with the cornea. Most irritation of the eye is from people with eye contacts. Nasal irritation mainly involves stuffiness after an eruption, along with throat irritation that contains sore throat issues. Short term death from gases when inhaled can cause asphyxiation, though long term damage from inhalation of gases include SO 2 that can cause prolonged respiratory disease. Fluoride from skin irritation and inhalation can cause permanent lung injury and osteoporosis of ligaments. Volcanic material also can enter the human body by ingestion from foods or soil, most commonly exposure of selenium. During an Iceland eruption from the Laki fissure, studies were done from the air pollutants (gases and aerosols) in the troposphere in 1783 (Fig 3). High gas contents flowed to Europe through a volcanogenic dry fog. Respiratory problems were noted with an extreme increase in asthma related dysfunctions. Eye irritation also increased with reports of tiring, stinging and tingling which was cause by sulfur dioxide(SO 2 ). Headaches and loss of appetite were also noted by the intake of fluorine and H 2 S. Overall, Europe was affected greatly due to the westerly wind that carried the pollutants, creating the widespread episodes of respiratory illnesses (Gratten 1999). The dry fog did contain sulfur, chlorine and fluorine which caused the reported symptoms from prolonged breathing. Volcanoes processes occur due to plate tectonics. The Earths lithosphere is broken into several tectonic plates which ride on the asthenosphere. The plates are either converging, diverging or sliding past each other. (Fig 2.) shows the three types of plate boundaries. Most commonly volcanoes form from convergent and divergent plate boundries. When a plate subducts under another plate, the subducting plate melts and magma rises creating volcanoes. During volcanic eruption, debris and gases are emmited. Debris can include pyroclastic flows, lahars, lava and ash. Pyroclastic flows and lahars can be the most deadly ejecta from a volcanic eruption causing incredible damage within 100km from the volcano. Gas emission, though very deadly, causes long term damage that can disrupt biological systems. Short term and long term deaths caused by volcanic eruptions is still a very common today. Understanding the warning signs of a volcano, using public strategies and mitigation plans to stay away from danger of a potential eruption is the best way to stay safe. The use of medical geology has made way to gather information of volcanoes and past health problems and give better insight on what to do to reduce volcano-related deaths. Weinstein and Cook, 2005, Volcanic Emissions and Health, in Selinus, 2005 Durand and Grattan, 1999, Extensive Respiratory Health Effects of Volcanogenic Dry Fog 1783 Inferred From European Documentary Sources Volcanic eruptions have occurred since before human have inhabited the earth. Though the most notable eruptions are from specific events that have been recorded. (Fig 1.) Gives a list of specific eruptions that have made a detrimental impact on landscapes and human health. Over the past 500 years as many as 250,000 death have been recorded (Weinsten 2005). Though medical geology is a relatively new topic of research, it has been observed for centuries. The history of heath effects are observed from old data with symptoms depending on the specific type of gas. Figure 1. Data from the deadliest historical volcanoes Figure 3. Common illnesses from case study. Figure 2. Basic Diagram of Plate Tectonics Figure 4. Health effects of Mt. Vesuvius eruption.