10. Regional Medical Geology: Global Health Trends
and Geographic Case Studies
Prepared by:
Alyssa Marquez
ABSTRACT
POLAR REGIONS
ARID 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).
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).
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.
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).
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).
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).
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:
CONTACT
Name: Alyssa Marquez
Organization: Western Oregon University
Email: amarquez05@wou.edu
• 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).
The content of soils and extreme levels
precipitation lead to geochemical responses
elements in the soil. Excesses and deficits
elements have direct effects on human health
well as the health of animals and plants.
of
of
of
as
• 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).
CONCLUSIONS
Figure 1. Endemic goiter.
Figure 2. Skin cancer.
Source: www.thachers.org/internal_medicine.htm
http://www.lib.uiowa.edu/hardin/md/skincancer.html
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.
REFERENCES
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.
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/
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.