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: pasakyi@ug.edu.gh

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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