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UGRC 144
Science and Technology in Our
Lives/Geohazards
Session 11 – Basic Principles of Medical
Geology and Trace Elements
Lecturer: Dr. Patrick Asamoah Sakyi
Department of Earth Science, UG
Contact Information: [email protected]
College of Education
School of Continuing and Distance Education
2014/2015 – 2016/2017
Session Overview
• In this session, we shall look at the basic principles
underlying medical geology. Human health can be
affected by long-term exposure to either an excess or a
deficiency of certain chemical and substances in the
geologic environment such as soil and groundwater.
• The session will focus on the pathways through which
trace elements from rocks, soils, and the atmosphere
enter the body.
• The emphasis will be on some of the basic activities that
we are involved in, which eventually result in the intake
of geologically produced elements and the effects on our
health.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 2
Session Outline
The key topics to be covered in the session are as
follows:
• Topic One – Basic Principles of Medical Geology
• Topic Two – Pathways through which Trace
Elements Enter the Body
• Topic Three - Controls of Trace Element Intake
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 3
Reading List
• Chapter 20 of Environmental Geology 4th Edition, Wm.
C. Brown Publishers – by Carla W Montgomery (1995)
• Unit 3, Sections 1 of UGRC 140 II Geohazards –
Institute of Continuing and Distance Education.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 4
Topic One
BASIC PRINCIPLES OF MEDICAL
GEOLOGY
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 5
Basic Principles of Medical Geology
• Geology is an earth science comprising the study of
solid Earth, the rocks of which it is composed, and the
processes by which they change
• Medical Geology is a discipline that examines
relationships between geologic materials, processes
and the occurrence of human and animal diseases.
• The use of geologic materials such as rocks, soils,
water and the atmosphere is universal.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 6
Basic Principles of Medical Geology
• It has been recognized that the human and animal
health can be affected through;
– Acute toxicity (e.g., short-term exposure to high
concentrations of toxic elements)
– Chronic effects (i.e., long-term exposure to toxic
elements)
– Excess or a deficiency of certain elements
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 7
Basic Principles of Medical Geology
Why do Medical Geologist relate the occurrence
of geologic materials and processes to human
and animal health?
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 8
Basic Principles of Medical Geology
• Before we proceed to answer the question, let us
look at the basic definitions of rock and minerals and
elements.
– In geology, rock is a naturally occurring solid
aggregate of one or more minerals.
– Minerals are solid inorganic substances, which
occur naturally with a definite chemical
composition and crystal structure.
– Minerals are composed of elements.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 9
Basic Principles of Medical Geology
• In geochemistry, a trace element is a
chemical element whose concentration is less
than 1000 parts per million (ppm) or 0.1% of a
rock's composition.
• In biochemistry, a trace element is a dietary
mineral that is needed in very minute quantities
for the proper growth, development, and
physiological functions of animals and humans.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 10
Basic Principles of Medical Geology
• In other words trace elements that are
required in minutes amounts (e.g., microgramto-milligrams per kilogram) are referred to as
micronutrients.
• But element that are required in fairly large
amounts (e.g., grams per kilogram), referred to
as macronutrients,
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 11
Basic Principles of Medical Geology
• Among the elements considered essential elements
to all animals and vegetation are;
Calcium (Ca)
Phosphorus(P)
Potassium (K)
Sulfur (S)
Sodium (Na)
Chlorine (Cl)
Magnesium (Mg)
Iron (Fe)
Cobalt (Co)
Copper (Cu)
Dr. Patrick A. Sakyi, Dept. of Earth Science
Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
Zinc (Zn)
Manganese (Mg)
Molybdenum (Mo)
Selenium (Se)
iodine (I)
Bromine (Br)
Slide 12
Basic Principles of Medical Geology
Functions of Some Elements
• Ca, P, Mg, F are required for structural functions in
bones and membranes.
• Na, K, and Cl are required for the maintenance of water
and electrolyte balance in cells.
• Zn, Cu, Se, Mn, and Mo are essential constituents of
enzymes or serve as carriers for ligands in metabolism.
• I and Cr serve as essential components of hormones.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 13
Basic Principles of Medical Geology
Functions of Some Elements
• The tissue levels of these elements tend to be
regulated within certain ranges, which are highly
dependent on several physiological processes..
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 14
Topic Two
PATHWAYS THROUGH WHICH
TRACE ELEMENTS ENTER THE BODY
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 15
Pathways through which Trace
Elements Enter the Body
• Trace elements get in the body mainly
through:
– The food chain
– Drinking water
– inhaled air from the atmosphere
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 16
Pathways through which Trace Elements
Enter the Body
The Food Chain
• Plants are the base on which the food chain is built. They
use photosynthesis to convert CO2 into the basic
molecules for metabolism such as sugars and amino
acids.
• Water and nutrients (elements) are acquired from the
soil and these are used to create new plant tissues.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 17
Pathways through which Trace Elements
Enter the Body
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 18
Pathways through which Trace Elements
Enter the Body
Drinking water – The Water Cycle
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 19
Pathways through which Trace Elements
Enter the Body
Inhaled Air from the Atmosphere
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 20
Topic Three
CONTROLS OF TRACE ELEMENT
INTAKE
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 21
Controls of Trace Element Intake
• Intake of trace elements are mainly controlled by
two factors, namely:
– Natural processes
– Activities of animals and humans
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 22
Controls of Trace Element Intake
Natural Processes
• Natural processes are mainly geological processes and
these include;
– the distribution of rocks with different elemental
compositions on the surface of the earth
– soil formation,
– the movement of water in the water cycle, and
– the intake of nutrient from soil by plants.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 23
Controls of Trace Element Intake
Activities of Humans (and Animals)
• These processes are attributed to the intake of food and
water, as well as other human actions and include;
– Diet
– Methods of storing food
– Mining
– Construction
– Pollution
– some agricultural practices.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 24
Summary
• Both natural and human-induced activities can result in
increased levels of trace elements. The natural processes
depend on the variation of the underlying geology, and
are difficult to control.
• However, human activities can modify trace elements in
many ways. For examples, soil pollution with metals such
as lead, zinc, copper, cadmium, arsenic and uranium, is
common near smelters and other ore-processing
facilities.
• The water pollution may be accompanied by
contamination of plants growing nearby.
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 25
END
Dr. Patrick A. Sakyi, Dept. of Earth Science
Slide 26