1. 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:

2. 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

3. 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

4. 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

5. Basic Principles of Medical Geology
Topic One
Basic Principles of Medical Geology
Dr. Patrick A. Sakyi, Dept. of Earth Science

6. 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

7. 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

8. 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

9. 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

10. 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

11. Basic Principles of Medical Geology
In other words trace elements that are required in minutes amounts (e.g., microgram- to-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

12. Basic Principles of Medical Geology
Among the elements considered essential elements to all animals and vegetation are;
Calcium (Ca)
Carbon (C)
Phosphorus(P)
Hydrogen (H)
Potassium (K)
Oxygen (O)
Sulfur (S)
Nitrogen (N)
Sodium (Na)
Zinc (Zn)
Chlorine (Cl)
Manganese (Mg)
Magnesium (Mg)
Molybdenum (Mo)
Iron (Fe)
Selenium (Se)
Cobalt (Co)
iodine (I)
Copper (Cu)
Bromine (Br)
Dr. Patrick A. Sakyi, Dept. of Earth Science

13. 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

14. 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

15. Pathways through which Trace Elements Enter the Body
Topic Two
Pathways through which Trace Elements Enter the Body
Dr. Patrick A. Sakyi, Dept. of Earth Science

16. 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

17. 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

18. Pathways through which Trace Elements Enter the Body
Dr. Patrick A. Sakyi, Dept. of Earth Science

19. Pathways through which Trace Elements Enter the Body
Drinking water – The Water Cycle
Dr. Patrick A. Sakyi, Dept. of Earth Science

20. Pathways through which Trace Elements Enter the Body
Inhaled Air from the Atmosphere
Dr. Patrick A. Sakyi, Dept. of Earth Science

21. Controls of Trace Element Intake
Topic Three
Controls of Trace Element Intake
Dr. Patrick A. Sakyi, Dept. of Earth Science

22. 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

23. 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

24. 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

25. 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

26. END
Dr. Patrick A. Sakyi, Dept. of Earth Science