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Medical Geology is a multi-disciplinary field of study in geology which studies the health effects of geologic materials and processes on humans. Such health effects can be good, or possibly hazardous. Medical Geology integrates professionals from medicine, geography and geology to handle problems accruing from the geology of an area. Three aspects of geology are relevant for a comprehensive study of health problems arising from the geology of a particular environment, namely: mineralogy, geochemistry and hydrogeology. Hazardous effects are caused by the excessiveness or deficiency of essential and non- essential trace elements such as: As, F-, I- , Se, Rn, Mn, Cd and Pb. For instance, excessiveness of arsenic in coals in China has lead to a toxic effect called arsenosis– the ulceration of the hands and feet; deficiency of iodine in the soil leads to goiter –the enlargement of the thyroid gland, while the excessiveness of fluoride in rocks leading to various forms of fluorosis which can manifest in the dissolution of apatite crystals of the enamel. This multidisciplinary field of geology also probes into the benefits and banes of eating soil, clay and shale –a practice called geophagy. Through the study of Medical Geology, however, some geologic materials have been found useful in the pharmaceutical, medical and cosmetic industries. These include medicinal/mineralized waters applied in the treatment of various skin diseases, such as rashes and eczema, as they contain elements such as Na, Ca, Mg, Cl, K, I, Br and Fe. Bathing in such mineralized waters―a process called balneotherapy―helps in taking these elements into the body through osmosis. Alkaline water production using tourmaline (Ca, K, Na)(Al, Fe, Li, Mg, Mn)3(Al, Cr, Fe, V)6(BO3)3(Si, Al, B)6O18(OH, F)4, and zeolite (Na2Al2Si3O10.2H2O ) is another important application of Medical Geology. Alkaline water negates the Oxidation-Reduction Potential of body toxins and increases the body pH up to 8. As most processed foodstuffs are acidic, the intake of alkaline water will raise the alkalinity of the body leading to increased longevity. Kaolin and [[bentonite]]-–the healing clays–-are applied in the treatment of gastrointestinal diseases; they have net negative surface charges with which they attract toxins. Toxins are then adsorbed into the structure of the clay mineral, and thus removed. Medical Geology also has important application in the manufacture of plaster of Paris. It is produced by calcining gypsum to produce a strong material used in holding fractured anatomical structures of the body in place until healing is completed. Production of milk of magnesia from brucite [Mg(OH)2]―magnesium hydroxide―is another important application of Medical Geology. Milk of magnesia is an antacid and interferes with the adsorption of folic acid in the stomach; it helps in maintaining the stomach pH and in the detoxification of the stomach.

Medical Geology is a multi-disciplinary field of study in geology which studies the health effects of geologic materials and processes on humans. Such health effects can be good, or possibly hazardous. Medical Geology integrates professionals from medicine, geography and geology to handle problems accruing from the geology of an area. Three aspects of geology are relevant for a comprehensive study of health problems arising from the geology of a particular environment, namely: mineralogy, geochemistry and hydrogeology. Hazardous effects are caused by the excessiveness or deficiency of essential and non- essential trace elements such as: As, F-, I- , Se, Rn, Mn, Cd and Pb. For instance, excessiveness of arsenic in [[coal]]s in China has lead to a toxic effect called arsenosis– the ulceration of the hands and feet; deficiency of iodine in the soil leads to goiter –the enlargement of the thyroid gland, while the excessiveness of fluoride in rocks leading to various forms of fluorosis which can manifest in the dissolution of apatite crystals of the enamel. This multidisciplinary field of geology also probes into the benefits and banes of eating soil, clay and shale –a practice called geophagy. Through the study of Medical Geology, however, some geologic materials have been found useful in the pharmaceutical, medical and cosmetic industries. These include medicinal/mineralized waters applied in the treatment of various skin diseases, such as rashes and eczema, as they contain elements such as Na, Ca, Mg, Cl, K, I, Br and Fe. Bathing in such mineralized waters―a process called balneotherapy―helps in taking these elements into the body through osmosis. Alkaline water production using tourmaline (Ca, K, Na)(Al, Fe, Li, Mg, Mn)3(Al, Cr, Fe, V)6(BO3)3(Si, Al, B)6O18(OH, F)4, and zeolite (Na2Al2Si3O10.2H2O ) is another important application of Medical Geology. Alkaline water negates the Oxidation-Reduction Potential of body toxins and increases the body pH up to 8. As most processed foodstuffs are acidic, the intake of alkaline water will raise the alkalinity of the body leading to increased longevity. Kaolin and [[bentonite]]-–the healing clays–-are applied in the treatment of gastrointestinal diseases; they have net negative surface charges with which they attract toxins. Toxins are then adsorbed into the structure of the clay mineral, and thus removed. Medical Geology also has important application in the manufacture of plaster of Paris. It is produced by calcining gypsum to produce a strong material used in holding fractured anatomical structures of the body in place until healing is completed. Production of milk of magnesia from brucite [Mg(OH)2]―magnesium hydroxide―is another important application of Medical Geology. Milk of magnesia is an antacid and interferes with the adsorption of folic acid in the stomach; it helps in maintaining the stomach pH and in the detoxification of the stomach.

==Introduction to medical geology==

==Introduction to medical geology==

Over the years, it has been observed that the environment man lives in affects his health. For instance, the people of Maputaland, South Africa, are plagued by nutrient-poor soil. Maize grown in this region has very low content of elements such as calcium, potassium and phosphorous.<ref>Selinus, O. and A. Frank, 2000. Medical Geology. Environmental Medicine, Joint Industrial Safety Council, 333, 164-183.</ref> This is as a result of low concentration of these elements in the rocks of that region. Countries in southern Africa also suffer from selenium deficiency in their soils. This accounts for the spread of HIV-1 virus in this zone as selenium which inhibits the replication of HIV-1 is lacking in their soil. Still in Africa, Kerala Province in Uganda is another region under the “hammer” of geology. Children in this province suffer from a ‘grave’ coronary heart condition called endomyocardial fibrosis (EMF). This epidemic is attributed to the deliberate eating of soil containing the element cerium.<ref name=Dvies>Davies, T. C., 2010. Medical Geology in Africa, ''in'' O. Selinus, R. B. Finkelman, and J. A. Centeno, eds., Medical Geology: A Regional Synthesis, 199–216.</ref>

Over the years, it has been observed that the environment man lives in affects his health. For instance, the people of Maputaland, South Africa, are plagued by nutrient-poor soil. Maize grown in this region has very low content of elements such as calcium, potassium and phosphorous.<ref>Selinus, O. and A. Frank, 2000. Medical Geology. Environmental Medicine, Joint Industrial Safety Council, 333, 164-183.</ref> This is as a result of low concentration of these elements in the rocks of that region. Countries in southern Africa also suffer from selenium deficiency in their soils. This accounts for the spread of HIV-1 virus in this zone as selenium which inhibits the replication of HIV-1 is lacking in their soil. Still in Africa, Kerala Province in Uganda is another region under the “hammer” of geology. Children in this province suffer from a ‘grave’ coronary heart condition called endomyocardial fibrosis (EMF). This epidemic is attributed to the deliberate eating of soil containing the element cerium.<ref name=Dvies>Davies, T. C., 2010. Medical Geology in Africa, ''in'' O. Selinus, R. B. Finkelman, and J. A. Centeno, eds., Medical Geology: A Regional Synthesis, 199–216.</ref>

China is not left aside in these problems. The country suffers from deficiencies and excessiveness of selenium in many parts of the country resulting in life-threatening health problems. China also suffers from the influx of arsenic into coal deposits whose domestic use has resulted to untold chronic health effects over the years.<ref name=Skinner />

China is not left aside in these problems. The country suffers from deficiencies and excessiveness of selenium in many parts of the country resulting in life-threatening health problems. China also suffers from the influx of arsenic into [[coal]] deposits whose domestic use has resulted to untold chronic health effects over the years.<ref name=Skinner />

The use of water from the Colorado Springs at the Pikes Peak in the Rocky Mountain region of USA had led to dental fluorosis amongst children. This condition arose as a result of meteoric waters that flowed over faulted granitic batholiths.<ref name=Fnklman2010b /> The meteoric waters ‘picked up’ fluoride from easily dissolved minerals at the fault and incorporated it into the flow. Fluoride was also injected into the Colorado Springs by fluoride-enriched fractured and faulted Cretaceous Pierre Shale that underlies the spring ([[:File:UNN_Medical_Geology_Fig_2.png|Figure 2]]).

The use of water from the Colorado Springs at the Pikes Peak in the Rocky Mountain region of USA had led to dental fluorosis amongst children. This condition arose as a result of meteoric waters that flowed over faulted granitic batholiths.<ref name=Fnklman2010b /> The meteoric waters ‘picked up’ fluoride from easily dissolved minerals at the fault and incorporated it into the flow. Fluoride was also injected into the Colorado Springs by fluoride-enriched fractured and faulted Cretaceous Pierre Shale that underlies the spring ([[:File:UNN_Medical_Geology_Fig_2.png|Figure 2]]).

Arsenosis refers to a range of adverse health effects caused by the intake of arsenic into the body system above the recommended values of 50μg/l.

Arsenosis refers to a range of adverse health effects caused by the intake of arsenic into the body system above the recommended values of 50μg/l.

In Guizhou Province, China, the cool, damp autumn weather forces villagers to bring their harvest of chili peppers and corn indoors to dry. They hang the peppers over unvented stoves which were formally fueled by wood. But, due to the destruction of forests, wood became scarce; so, the villagers turned to the plentiful outcrops of coal for heating, cooking and drying their harvests.<ref name=Fnklman2010a /> Unknowingly to them, mineralizing solutions in this area had deposited enormous concentrations of arsenic − up to 35,000 ppm − and other trace elements on the coals. It should be noted that normal coals have arsenic concentration of 20 ppm. Consumption of the chili peppers dried over these arsenic-rich coals exposed the natives to arsenosis. The dried chili peppers contained up to 500 ppm of arsenic whereas normal chili peppers contain less than 1 ppm of arsenic.<ref name=Wuyi /> In addition, inhalation of arsenic-laden indoor air derived from coal combustion has increased the toll of arsenic poisoning in the region.<ref name=Fnklman2005 />

In Guizhou Province, China, the cool, damp autumn weather forces villagers to bring their harvest of chili peppers and corn indoors to dry. They hang the peppers over unvented stoves which were formally fueled by wood. But, due to the destruction of forests, wood became scarce; so, the villagers turned to the plentiful outcrops of [[coal]] for heating, cooking and drying their harvests.<ref name=Fnklman2010a /> Unknowingly to them, mineralizing solutions in this area had deposited enormous concentrations of arsenic − up to 35,000 ppm − and other trace elements on the coals. It should be noted that normal coals have arsenic concentration of 20 ppm. Consumption of the chili peppers dried over these arsenic-rich coals exposed the natives to arsenosis. The dried chili peppers contained up to 500 ppm of arsenic whereas normal chili peppers contain less than 1 ppm of arsenic.<ref name=Wuyi /> In addition, inhalation of arsenic-laden indoor air derived from coal combustion has increased the toll of arsenic poisoning in the region.<ref name=Fnklman2005 />

Chemical and mineralogical tests conducted showed that there were many arsenic-bearing minerals in the coals, although, much of the arsenic is bound to the organic matrix of the coals. This observation presented two problems namely: (1) since arsenic is bound to the organic matrix, conventional reduction methods of removing arsenic was ineffective; (2) the visually observable pyrite on the coal samples was not reliable in establishing arsenic-rich samples.

Chemical and mineralogical tests conducted showed that there were many arsenic-bearing minerals in the coals, although, much of the arsenic is bound to the organic matrix of the coals. This observation presented two problems namely: (1) since arsenic is bound to the organic matrix, conventional reduction methods of removing arsenic was ineffective; (2) the visually observable pyrite on the coal samples was not reliable in establishing arsenic-rich samples.