Medical geology

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Medical geology is an interdisciplinary scientific field studying the relationship between natural geological factors and their effects on human and animal health. [1] The Commission on Geological Sciences for Environmental Planning defines medical geology as "the science dealing with the influence of ordinary environmental factors on the geographical distribution of health problems in man and animals." [2]

Contents

In its broadest sense, medical geology studies exposure to or deficiency of trace elements and minerals; inhalation of ambient and anthropogenic mineral dusts and volcanic emissions; transportation, modification and concentration of organic compounds; and exposure to radionuclides, microbes and pathogens. [3]

History

Many have deemed medical geology as a new field, when in actuality it is re-emerging. Hippocrates and Aristotle first recognized the relationship between human diseases and the earth's elements. [4] This field ultimately depends on a number of different fields coming and working together to solve some of the earth's mysteries. The scientific term for this field is hydrobiogeochemoepidemiopathoecology; [5] however, it is more commonly known as medical geology. [4] It was established in 1990 by the International Union of Geological Sciences. [2] Paracelsus, the "father of pharmacology" (1493–1541), stated that "all substances are poisons, there is none which is not a poison. The right dosage differentiates a poison and a remedy." [2] This passage sums up the idea of medical geology. The goal of this field is to find the right balance and intake of elements/minerals in order to improve and maintain health. [2]

Examples of research in medical geology include:[ citation needed ]

Recently, a new concept of "geomedical engineering" has been introduced in medical geology through a paper titled "Geomedical Engineering: A new and captivating prospect". [6] It provides the fundamentals of engineering applications to the medical geology issues. [7]

Environment and human health

It is widely known that the state of our environment affects us in many ways. Minerals and rocks have an impact on human and animal populations because that is what the earth is composed of. [2] Medical geology brings professionals from both the medicine field and the geology field to help us understand this relationship. [8] There are two priorities that have been established within the medical geology field, "(1) the study of trace elements, especially their bioavailability and (2) a need to establish baseline, or background levels of contaminants/xenobiotics/potentially harmful but naturally occurring materials in water, soil, air, food, and animal tissue." [4] The elements and minerals in the land affect people and animals immensely, especially when there is a close relationship between the two. Those who depend heavily on the land are faced with one of two problems. First, those who live in places such as Maputaland, South Africa are exposed to heavily impoverished soils which result in a number of diseases caused by mineral imbalances. [2] Secondly, those in areas such as India and Bangladesh are often exposed to an excess of elements in the land, resulting in mineral toxicity. [2]

All living organisms need some naturally occurring elements; however, excessive amounts can be detrimental to health. [9] There is a direct link between health and the earth because all humans ingest and breath in these chemicals and for the most part it is done unknowingly. [9]

Sources of chemical exposure

There are many ways in which humans come into contact with the earth's elements and below are only a few ways in which we become exposed to them.

Diseases

Iodine deficiency

One of the biggest geochemical diseases is iodine deficiency. Thirty percent of the world is at risk for it and insufficient intake is the most common cause of intellectual disability and brain damage. [2] The sea is a major source of iodine and those who are further from it are at a disadvantage. [2] Another source of it is in soil; however, goitrogens such as humus and clay trap the iodine, making it hard for people to access it. [2] Some cultures actually consume the earth's minerals by eating soil and clay; this is known as geophagy. [2] It is most common in the tropics, especially among pregnant women. [2] The Ottomac people of South America engage in this practice and none have suffered from any health problems related with mineral/ Iodine deficiency. [2]

Cardiovascular disease

Cardiovascular disease has often been linked to water hardness as the main cause. [2] Water hardness means that there is magnesium in the water with calcium playing a role. [2] Some research has completely discredited this evidence, and has found that the more magnesium in the water the less chance of death cardiovascular disease. [2]

Radiation

Natural radiation is found everywhere; it is in the air, water, soil, rocks, minerals and food. [2] The largest amount of radiation comes from radon. [2] Certain places are called 'high background radiation areas' (HBRAs), such as Guarapari, Southwest of France, Ramsar, parts of China, and Kerala Coast. [2] People living in these areas however have not shown any health deficiencies and in some cases are even healthier and live longer than those not in HBRAs. [2]

Other issues

Among the problems presented there are also issues with fluoride in Africa and India, arsenic in Argentina, Chile, and Taiwan, selenium in areas of the United States, Venezuela, China and nitrate in agricultural areas. [10] As medical geology grows it may become more important to the medical field in relation to the issue of diseases. In addition to deficiencies of particular minerals, dietary excesses of certain elements occurring in specific geographic regions can also be harmful to human health, as per the examples listed below:

International Medical Geology Association

"The International Medical Geology Association (IMGA) aims to provide a network and a forum to bring together the combined expertise of geologists and earth scientists, environmental scientists, toxicologists, epidemiologists, and medical specialists, in order to characterize the properties of geological processes and agents, the dispersal of geological material and their effects on human population." [8] IMGA was founded in 2006 and manages affairs and funds, plans conferences, elections and publications, and they are also a way of encouraging growth and recognition in the field. [8] Although it was founded in 2006, it was a work in progress for ten years when a working group of medical geology was established by the International Union of Geological Sciences (IUGS) in 1996. [9] The goal of the working group was to advertise and make people aware of the harmful effects the environment has on our health. [9]

Related Research Articles

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.

<span class="mw-page-title-main">Iodine</span> Chemical element, symbol I and atomic number 53

Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at 114 °C (237 °F), and boils to a violet gas at 184 °C (363 °F). The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek Ιώδης 'violet-coloured'.

<span class="mw-page-title-main">Radon</span> Chemical element, symbol Rn and atomic number 86

Radon is a chemical element; it has symbol Rn and atomic number 86. It is a radioactive noble gas and is colorless and odorless. Of the three naturally occurring radon isotopes, only radon-222 has a sufficiently long half-life for it to be released from the soil and rock, where it is generated. Radon isotopes are the immediate decay products of radium isotopes. Radon's most stable isotope, radon-222, has a half-life of only 3.8 days, making radon one of the rarest elements. Radon will be present on Earth for several billion more years, despite its half-life being a mere 3.8 days, because it is constantly being produced as a step in the decay chain of uranium-238, and that of thorium-232, each of which is an extremely abundant radioactive nuclide with a half-life of several billion years. The decay of radon produces many other short-lived nuclides, known as "radon daughters", ending at stable isotopes of lead. Radon-222 occurs in significant quantities as a step in the normal radioactive decay chain of uranium-238, also known as the uranium series, which slowly decays into a variety of radioactive nuclides and eventually decays into lead-206, which is stable. Radon-220 occurs in minute quantities as an intermediate step in the decay chain of thorium-232, also known as the thorium series, which eventually decays into lead-208, which is stable.

A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons to release it as a conversion electron; or used to create and emit a new particle (alpha particle or beta particle) from the nucleus. During those processes, the radionuclide is said to undergo radioactive decay. These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for a collection of atoms of a single nuclide the decay rate, and thus the half-life (t1/2) for that collection, can be calculated from their measured decay constants. The range of the half-lives of radioactive atoms has no known limits and spans a time range of over 55 orders of magnitude.

A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates, lipids, proteins, and fermentation products, leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.

A period 5 element is one of the chemical elements in the fifth row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as rhodium.

<span class="mw-page-title-main">Mineral (nutrient)</span> Chemical element required as an essential nutrient by organisms to perform life functions

In the context of nutrition, a mineral is a chemical element. Some "minerals" are essential for life, most are not. Minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, and essential amino acids. The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. The remaining elements are called "trace elements". The generally accepted trace elements are iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium; there is some evidence that there may be more.

<span class="mw-page-title-main">Radioactive contamination</span> Undesirable radioactive elements on surfaces or in gases, liquids, or solids

Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases, where their presence is unintended or undesirable.

<span class="mw-page-title-main">Nuclear fission product</span> Atoms or particles produced by nuclear fission

Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release of heat energy, and gamma rays. The two smaller nuclei are the fission products..

<span class="mw-page-title-main">Environmental hazard</span> Harmful substance, a condition or an event

An environmental hazard is a substance, state or event which has the potential to threaten the surrounding natural environment or adversely affect people's health, including pollution and natural disasters such as storms and earthquakes. It can include any single or combination of toxic chemical, biological, or physical agents in the environment, resulting from human activities or natural processes, that may impact the health of exposed subjects, including pollutants such as heavy metals, pesticides, biological contaminants, toxic waste, industrial and home chemicals.

Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as congenital iodine deficiency syndrome due to untreated congenital hypothyroidism, which results in developmental delays and other health problems. Iodine deficiency is an important global health issue, especially for fertile and pregnant women. It is also a preventable cause of intellectual disability.

<span class="mw-page-title-main">Isotopes of iodine</span> Nuclides with atomic number of 53 but with different mass numbers

There are 37 known isotopes of iodine (53I) from 108I to 144I; all undergo radioactive decay except 127I, which is stable. Iodine is thus a monoisotopic element.

<span class="mw-page-title-main">Agricultural soil science</span> Branch of soil science

Agricultural soil science is a branch of soil science that deals with the study of edaphic conditions as they relate to the production of food and fiber. In this context, it is also a constituent of the field of agronomy and is thus also described as soil agronomy.

<span class="mw-page-title-main">Environmental radioactivity</span> Radioactivity naturally present within the Earth

Environmental radioactivity is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 (90Sr) and technetium-99 (99Tc), are only found on Earth as a result of human activity, and some, like potassium-40 (40K), are only present due to natural processes, a few isotopes, e.g. tritium (3H), result from both natural processes and human activities. The concentration and location of some natural isotopes, particularly uranium-238 (238U), can be affected by human activity.

<span class="mw-page-title-main">Radium and radon in the environment</span> Significant contributors to environmental radioactivity

Radium and radon are important contributors to environmental radioactivity. Radon occurs naturally as a result of decay of radioactive elements in soil and it can accumulate in houses built on areas where such decay occurs. Radon is a major cause of cancer; it is estimated to contribute to ~2% of all cancer related deaths in Europe.

Uranium in the environment is a global health concern, and comes from both natural and man-made sources. Mining, phosphates in agriculture, weapons manufacturing, and nuclear power are sources of uranium in the environment.

<span class="mw-page-title-main">Lunar soil</span> Rock dust covering the Moon

Lunar soil is the fine fraction of lunar regolith found on the surface of the Moon and contributes to the Moon's tenuous atmosphere. Lunar soil differs in its origin and properties significantly from terrestrial soil.

After irrigation projects diverted water from the Aral Sea it began to dry up and left behind salts, other minerals, and toxins in the soil. These not only contaminated the soil but also were picked up by winds and storms, and traveled to other areas, including over crop lands. This has led to increased health problems like respiratory diseases and cancers, among others. The change in the size of the Aral has also affected the local climate and resulted in increased occurrence and worsening of storms.

The health effects of radon are harmful, and include an increased chance of lung cancer. Radon is a radioactive, colorless, odorless, tasteless noble gas, which has been studied by a number of scientific and medical bodies for its effects on health. A naturally-occurring gas formed as a decay product of radium, radon is one of the densest substances that remains a gas under normal conditions, and is considered to be a health hazard due to its radioactivity. Its most stable isotope, radon-222, has a half-life of 3.8 days. Due to its high radioactivity, it has been less well studied by chemists, but a few compounds are known.

Exposure to ionizing radiation is known to increase the future incidence of cancer, particularly leukemia. The mechanism by which this occurs is well understood, but quantitative models predicting the level of risk remain controversial. The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert; if correct, natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a close second. Additionally, the vast majority of non-invasive cancers are non-melanoma skin cancers caused by ultraviolet radiation. Non-ionizing radio frequency radiation from mobile phones, electric power transmission, and other similar sources have been investigated as a possible carcinogen by the WHO's International Agency for Research on Cancer, but to date, no evidence of this has been observed.

References

  1. ↑ "Medical geology". British Geological Survey . Archived from the original on 7 September 2013. Retrieved 27 August 2023.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Dissanayake, Chandrasekara (5 August 2005). "Of Stones and Health: Medical Geology in Sri Lanka". Science. 309 (5736): 883–885. doi:10.1126/science.1115174. PMID   16081722.
  3. ↑ Finkelman, Robert B.; Skinner, H. Catherine W.; Plumlee, Geoffrey S.; Bunnell, Joseph E. (November 2001). "Medical Geology". Geotimes.
  4. 1 2 3 Bunnell, Joseph (March 2004). "Medical Geology: Emerging Discipline on the Ecosystem--Human Health Interface". EcoHealth. 1 (1): 15–18. doi:10.1007/s10393-004-0068-8. S2CID   5881278.
  5. ↑ Goovaerts, P. (August 2014). "Geostatistics: a common link between medical geography, mathematical geology, and medical geology". Journal of the Southern African Institute of Mining and Metallurgy. 114: 605–612. ISSN   2225-6253. PMC   4339079 . PMID   25722963. S2CID   36283381.
  6. ↑ Kamel Boulos, Maged N.; Le Blond, Jennifer (28 January 2016). "On the road to personalised and precision geomedicine: medical geology and a renewed call for interdisciplinarity". International Journal of Health Geographics. 15 5: 5. doi: 10.1186/s12942-016-0033-0 . ISSN   1476-072X. PMC   4730661 . PMID   26819075.
  7. ↑ Ur Rehman, Atteeq (June 2009). "Geomedical Engineering: A new and captivating prospect" (PDF). Medical Geology Newsletter 14: 22–23. ISSN   1651-5250. Archived from the original (PDF) on 28 October 2022.
  8. 1 2 3 "IMGA". medicalgeology.org.
  9. 1 2 3 4 5 6 7 Selinus, Olle (February 2007). "Medical Geology: An Opportunity for the Future". Ambio: A Journal of the Human Environment. 36 (1): 114–116. doi:10.1579/0044-7447(2007)36[114:mgaoft]2.0.co;2. PMID   17408204. S2CID   1245988.
  10. ↑ Alloway, B.J. (2005). Essentials of Medical Geology: Impacts of the Natural Environment on Public Health. Amsterdam, Boston: Elsevier Academic Press. ISBN   0126363412.
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