Name: Alyssa Marquez Organization: Western Oregon University Email: amarquez05@wou

1. 10. Regional Medical Geology: Global Health Trends and Geographic Case Studies Prepared by: Alyssa Marquez ARID REGIONS ABSTRACT POLAR REGIONS TROPICAL REGIONS The field of medical geology studies the effects of geological materials on the health of both humans and animals. Plate tectonics, crustal lithology, and climate of any given region are spatially variable and have a direct influence on the input of elements into the soil, air, and water. Health issues associated with regional geologic variation have been observed all over the world. Tectonic and surface hazards (e.g. earthquakes, volcanic eruptions, floods, landslides, tsunamis) catastrophically impact social infrastructure, and in turn spawn a host of public health issues. Other examples include degraded water quality and anomalous concentrations of essential elements that also lead to adverse health effects. This paper provides a sampling of regional case studies in medical geology and demonstrates the geographic variability of health conditions associated therein. Located at 66 degrees North and South, polar regions are marked by little sunlight, low air temperature, and strong winds. These polar deserts possess infertile soils and low mineral content in water, making unfavorable environments for plant and animal life (Komatina, 2004). Common diseases afflicting humans in polar regions largely result as factors of climate. Such conditions include: cooling of the body, including hypothermia; diseases of the nervous system; chronic bronchitis, pneumonias; anemia (Komatina, 2004). Coronary diseases are often prevalent in polar regions, with deaths increasing in cold seasons. A sudden drop of atmospheric pressure may cause cardiac arrest (Komatina, 2004). Arid regions encompass the northern half of Africa, much of Australia, the Arabian platform, the mountainous regions of North America, South America, and Asia. Arid regions have high air temperatures, little precipitation and very little surface water. There exists an abundance of sunlight, of heat, and fertile soil, yet an absence of vegetation (Komatina, 2004). Common diseases in arid regions have climatically influenced pathologies. Extended periods of high temperatures in conjunction with dry air may lead to heat stroke, urinary stones and skin cancer (Figure 2) (Komatina, 2004). The characteristics of diseases in arid regions are directly related to geochemical factors: • Goiter and fluorosis – caused by iodine or fluorine deficits (Komatina, 2004). • Endemic cancers – frequently of the esophagus, caused by high amounts of quartz in dust; nitrates in soil are also a cause of cancers of the esophagus and stomach (Komatina, 2004). • Urolithiasis – endemic in many regions due to mineralization of drinking water (Komatina, 2004). The earth’s tropical regions include Equatorial Africa, South and Southeast Asia, Central America and South America. Tropical regions are characterized by high precipitation, high heat and as a result of those factors as well as enriched soils, high productivity. The content of soils and extreme levels of precipitation lead to geochemical responses of elements in the soil. Excesses and deficits of elements have direct effects on human health as well as the health of animals and plants. • Sodium deficit – in water and food, amplified by sweating. Low sodium content in blood can lead to exhaustion of nervous system (Komatina, 2004). • Iron deficit – anemia is common. Iron is in plant material but is “poorly assimilated by the human organism from plant food” (Komatina, 2004). • Calcium and iodine deficit – in soil, leads to increase of dental cavities, endemic goiter (widely seen in West Africa) (Komatina, 2004). • Fluorine excess – widely seen in India; endemic Fluorosis Belt; fluorine-rich groundwater. Leads to dental and skeletal deformations (Figures 3 and 4) (Saravanan, 2008). FOREST BELT Much of the Northern Hemisphere is included in the forest belt, which is characterized by a warm, damp, moderate climate. The soils of the forest belt range from calcic to acidic-calcic, or transitional soils (Komatina, 2004). Calcic soils form in landscapes developed atop of limestones and dolomites (Komatina, 2004). The surface water and groundwater are rich in mineral such as calcium. Calcium has a positive influence on the development of organisms, soil, and water quality (Komatina, 2004). Transitional soils are less favorable for developing and sustaining life. Compounds that are important for animal and plant life are easily leached from transitional soils and transported to rivers through groundwater systems (Komatina, 2004). As a result, soils are poor in elements necessary for vegetation. Elements with low concentrations in transitional soils include: • Calcium – leads to shorter stature in animals, weak bones, osteoporosis, rickets (Komatina, 2004). • Cobalt – leads to Vitamin B-12 deficiency (Komatina, 2004). • Iodine – causes low functioning thyroid glands, development of endemic goiter (Figure 1) in both humans and animals (Komatina, 2004). CONCLUSIONS Medical geology studies the effects of geologic materials on the health of living organisms. Geologic factors are the cause of the world’s most widespread diseases. By examining regional geochemical characteristics it is possible to determine causes for many diseases and conditions that afflict human beings. Excesses and deficits of elements in soils, water and plants have direct effects on the health of humans and animals. Figure 1. Endemic goiter. Source: www.thachers.org/internal_medicine.htm Figure 2. Skin cancer. http://www.lib.uiowa.edu/hardin/md/skincancer.html REFERENCES CONTACT Bowman, Charlotte A., Bobrowsky, Peter T., Selinus, Olle, Medical Geology: New Relevance in the Earth Sciences, Episodes, v. 26, no. 4, p. 270-278. Davies, T.C., 2003, Case Study: Some Environmental Problems of Geomedical Relevance in East and Southern Africa, Geology and Health, p. 139-144. Komatina, Miomir M., 2004, Medical Geology: Effects of Geological Environments on Human Health, Elsevier B.V.: Netherlands, p. 305-325, 335-369,370-396. Saravanan, S, et al., 2008, Prevalence of Dental Fluorosis Among Primary School Children in Rural Areas of Chidambaram Taluk, Cuddalore District, Tamil Nadu, India: Indian Journal of Community Medicine, p. 146-150. Name: Alyssa Marquez Organization: Western Oregon University Email: amarquez05@wou.edu Figure 3. Dental fluorosis. Source: http://gear.dyndns.org/~spencer/ Images/fluorosis%20teeth8.jpg Figure 4. Skeletal fluorosis in a child. Source: http://www.fluorideandfluorosis.com/