Earth science seems to have little to do with human health problems. In fact, rock is the main substance that constitutes the earth's surface, and it is rich in important minerals and chemical elements. Most of these elements enter the human body through air, food and water. Rocks will be broken by weathering, thus forming soil on which crops and livestock depend. Drinking water flows through rocks and soil, which is part of the water cycle. At the same time, most of the dust and some gases in the atmosphere are also formed by geological movements.
Earth and health, or "medical geology", involves the relationship between natural geological factors and human and animal health, and can also enhance our understanding of the impact of environmental factors on the regional distribution of health problems. Medical geology unites geoscientists with medical/public health researchers to study geological substances (rocks, minerals and water) and health problems caused or aggravated by geological processes (such as volcanic eruptions, earthquakes and atmospheric dust).
Medical geology cannot be regarded as a "re-emerging" topic. For centuries, the relationship between rocks, minerals and human health has been widely known. In ancient times, there were written records in China, Egypt, Islam and Greece, which recorded the treatment methods extracted from various rocks and minerals and various health problems they might cause. More than 2000 years ago, China recorded and described the medicinal uses of 46 different minerals.
Parachelsus (1493 ~1541) was the first person to establish the basic laws of toxicology. He said: "All substances are poisonous, and nothing is not poison. The correct dose is the key to distinguish poison from prescription. " Therefore, whether the content of various elements increases or decreases, it will bring biological side effects.
3.2 Earth and Health-One of the Preferred Themes of the International Year of Earth
It is urgent to apply geochemical and mineralogical techniques to the study of pathology and in vivo pathways. We must more completely reveal the relationship between the quality of the earth's materials and human health. Especially the relationship between the excess or deficiency of some elements, ions and important micronutrients (such as iodine, selenium, iron, arsenic, radon, etc.) and human health. ), and components that are ubiquitous all over the world but have unclear advantages and disadvantages (such as timely) need to be highly valued.
Scientists will benefit greatly from their experience in filling the gap and breaking through obstacles between this interdisciplinary research branch and social related scientific fields. Partners will include geoscientists, medical researchers, pathologists, toxicologists, epidemiologists, medical geographers, veterinarians, dentists and wildlife managers.
In order to make great progress in the research of related majors, it is necessary to combine them closely. It is also necessary for the earth science community to cooperate closely with professional and technical personnel in the field of public health.
Can we identify the environmental factors of known health problems and work with biomedical/public health researchers to find ways to prevent or alleviate these problems?
Cooperation with geologists and medical scientists will bring many valuable technologies to solve the health problems caused by geological materials and geological processes. Although some of these technologies are not surprising to many other disciplines, doctors can make better use of them in different ways or from different angles, which is both a challenge and a hope for human beings. For example, people in the field of environmental sanitation use a large number of tools and information (databases) to deal with diseases spread by vectors, and build models of pollution diffusion in surface water and groundwater. By combining earth science and public health professionals, we can find ways to solve the environmental causes of health problems.
3.3 Soil, sediment and water
How can we determine the elements in soil, sediment and water that may have adverse effects on health and distinguish whether their geochemical content is "high" or "low"? What are their key links with human and animal health?
There are many examples to illustrate this connection between "surplus" and "shortage".
Volcanoes and their related activities bring metals and other elements from the depths of the earth to the surface. Volcanic ash introduces some new elements into the environment and may increase the toxicity of the food chain. Volcanic ash cloud will bring serious global health risks and lead to short-term or long-term health problems: from mild pneumonia to pneumoconiosis.
Earthquakes also directly or indirectly threaten health, but the indirect effects are the most worthy of attention. Many of these problems are caused by landslides caused by earthquakes, which activate some elements and other potentially dangerous components, such as fungi, leading to "valley fever".
High levels of arsenic in drinking water have brought serious health problems to millions of people in Asia. In order to change this situation, it is necessary to study the source rock of arsenic leaching and the conditions of arsenic activation in detail. If the public health department wants to identify aquifers with similar characteristics, it is very important to answer the above and related questions, so as to identify the threatened population more accurately.
Radon is another element. It is an invisible, colorless and odorless radioactive gas, which easily escapes through soil and may enter houses. It is the biggest potential threat in natural radiation. The most common effect of radon radiation is lung cancer.
Radon and arsenic are just two examples of dangerous elements. In real life, there are other elements in rocks and water, which are also very important to human health. For example, the lack of certain elements may lead to serious health problems. People in mountainous areas once lacked iodine, because iodine was easily filtered out of thin soil layers in exposed areas with abundant rain. Another example is cardiomyopathy called Keshan disease. This disease was first discovered in the early 20th century, and it was caused by selenium deficiency. In 1960s, the disease was questioned from the perspective of geological interpretation. Subsequently, it was found that the content of selenium in bedrock, soil and natural water in the affected areas was very low. For a period of time, patients were treated with selenium supplementation, which achieved great success.
3.4 Fluoride and Health
Fluorine is an essential element in people's diet. For a long time, tooth decay has been related to fluoride deficiency, so fluoride toothpaste has its curative effect. Some countries also add fluorine to water supply (to increase the low content in natural water).
However, there are also many reports about the adverse consequences of excessive fluorine (related to the use of fluorine-rich groundwater). Dental fluorosis is a disease caused by excessive absorption of fluoride at teething age. This is the earliest visible sign of excessive fluoride exposure in children. Fluorine produces fluorinated teeth by destroying ameloblasts. The destruction of such cells will make the mineralization of teeth disorder, thus increasing the pores of enamel and reducing the mineral content. In some extreme cases, bones can also be damaged (skeletal fluorosis).
Many people in developing countries suffer from chronic fluorosis. Some people think that the fluorine content in the drinking water of more than 200 million people in the world exceeds the recommended value of the World Health Organization. The health problems caused by burning coal at home and releasing fluorine into the air are quite common.
Some places have fluorosis of teeth and bones, with more than100000 victims. The reason may be that they spread the grain to dry on an unventilated stove, which is burned with coal with high fluorine content. The use of clay (high fluorine residue after limestone is strongly leached) as a binder for making coal bricks further aggravates this problem.
Working together with geological scientists, health professionals can really help those who suffer from health damage caused by fluorine (and other elements).
3.5 The air we breathe
We live in a dusty world, and the dust (deposition) that falls in our yard may come from thousands of miles away. Dust is a global phenomenon. Sandstorms originating in Africa reach the Alps regularly, while those in Asia can reach California within a week, and some will eventually cross the Atlantic to Europe. Mineral dust has many effects on human life and health, including:
(1) Change the radioactive balance of the earth (dust can reflect heat and make the earth cool);
(2) spreading germs to densely populated areas;
(3) Depositing weathered sediments on primitive coral reefs;
(4) air quality has generally deteriorated;
(5) provide some basic nutrients for the tropical rain forest;
(6) toxic substances.
Dust can be made into flowing animals by human or natural factors. When we disturb the earth's surface or uproot its vegetation, we make dust flow. Changes in climatic conditions play an important role, because natural changes are caused by suitable humidity and wind speed. Although vegetation plays an important role in controlling the flow direction of dust, vegetation itself is also affected by climate, human activities and other factors.
If we try to reduce the adverse consequences of dust, we must have a better understanding of it, including some functions that can control its source and migration process, as well as its negative effects. As a good start, we can at least determine and control the sandstorm caused by human activities.
3.6 How extensive is the impact of global dust on health?
At present, the exact Chetter sign and epidemiological knowledge of the impact of atmospheric dust on health are still not clear. Very fine particles can penetrate deep into the lungs, causing lung diseases such as pneumoconiosis and asbestosis. The higher the dust content, the higher the chronic respiratory diseases and related mortality.
The first reported cases of natural (non-occupational) pneumoconiosis were some Bedouins in the Sahara desert in the mid-20th century. Since then, this case has also been found among Pakistani farmers, California farm workers, Ladakh villagers, residents of thar desert (northwest India) and residents of northern China. At present, there is no quantitative data about natural pneumoconiosis, but some studies show that the incidence of pneumoconiosis in some villages in Ladakh exceeds 22% of the total population.
3.7 Can we predict the health problems caused by inhaling dust and how to reduce this threat?
In order to get a satisfactory answer to the above questions, we must make a more in-depth study of surface dust and atmospheric dust. It is necessary to find out the source and settlement area of dust on land and determine the change mode of dust movement (dust flow) under various climatic conditions in the near future. We still have a lot of work to study on how to transport dust and the influence of atmospheric dust on the radiation balance of the earth. The professional knowledge required for this work involves surface interaction, geochemical/isotope fingerprinting technology, climate analysis, remote sensing and in-depth investigation of atmospheric radiation and dynamics. Adding sand and dust factors (from source to subsidence) to climate model will help us to deepen our understanding and make predictions on different time scales (from weeks to centuries). This problem is also closely related to "natural disasters", one of the top ten themes of the International Year of Earth.
Facing the health problems caused by geological materials and geological processes. How can we enhance public confidence? The universality of health problems caused by geological materials and geological processes is beyond people's imagination. It is estimated that the health of 3 billion people in the world is affected by geological factors, but most of them are not known to the public. This information is very important not only to ordinary people, but also to doctors, policy makers and planners. If geological factors are considered in health planning, many negative effects can be avoided.
3.8 How to establish links between developed and developing countries in order to find solutions to the same health problems?
Scientists from developed and developing countries will unite to deal with this global problem. It is an effective way to offer international short-term training courses. This short training course was very successful in sharing the latest information about the relationship between metal ions and trace elements and their impact on the environment and public health. The training contents include: environmental toxicology, environmental pathology, geochemistry, geological environment epidemiology, the degree, mode and consequences of exposure to metal ions and analytical methods. This activity can also be extended to some projects involving underdeveloped countries and local scientists, especially those places that urgently need to deal with health problems caused by geological factors.