The relationship between the natural environment and the human health has been suggested for centuries.
People are very conscious of a range of geo hazards, no matter where they occur. The announcements made through radio, television and even now internet arrives within hours of an event advising the vulnerable people about the impeding dangers.
Early warning systems are used to moderate such apparent disasters provided detection systems are appropriately situated and monitored and the population at risk timely alerted. This public awareness and vociferation have given way to the realization that we need a better understanding of links between the dynamics of mother Earth and its inhabitants.
The understanding of relationship between the natural environment and the human health has been suggested for centuries. Greeks and Romans believed “ill winds” punished seafarers and knew that some vapors could kill. The health of billions of people around the globe is affected to varying degrees by our natural environment, a major component of which is the geology of the earth. Geological materials such as rocks, minerals, and water and geological processes such as volcanic eruptions, earthquakes and dust portray key roles in a domain of environmental health issues that impact the health and wellbeing of people. As a response to this global concern on importance of geological factors on health, coupled with general lack of appreciation in understanding the geology, International Commission on Geological Sciences for Environmental Planning framed in 1996 International Working Group on Medical Geology, which subsequently led to the establishment of International Medical Geology Association (IMGA) in 2006. Medical Geology is an emerging and promising interdisciplinary scientific field focusing on the relationship between natural geological environments and their health effects on human beings, livestock and plant kingdom including understanding the influence of environmental factors on the geographical distribution of health problems which involves geoscientists, medical professionals and other disciplines. Medical geology was included as one of the ten main themes of the International Year of Planet Earth (2007-2009) under the title “Earth and Health – for a safer environment under the coordination of IUGS and UNESCO.
There are direct links between geochemistry and health via food chain and inhalation of atmospheric dust and gases. The 92 naturally occurring chemical elements are found in different types of rocks (building blocks of earth) composed of different mineral assemblages. Many of these elements are essential to plant, animal and human health in small doses. The geochemical pathways of the essential trace nutrients that enter the food chain are clear and being intimately linked to the immediate geological environment. For example, the trace elements occur naturally in rocks, soils, gases and waters in both harmless and harmful forms and concentrations. They are important in environmental health because they perform several vital functions e.g, calcification of bone, blood coagulation, neuromuscular irritability, acid-base-equilibrium, fluid balance and osmotic regulation etc. Certain elements are integral components of biologically important compounds such as hemoglobin (Fe), thyroxin (I), insulin (Zn) and vitamin B12 (Co). Several metals also participate as cofactors for enzymes in metabolism (e.g. Mg, Mn, Cu, Zn, K) and some are essential constituents of certain enzymes (e.g. Co, Mo, Se). However, it is pertinent to mention here that the 92 naturally occurring elements are not distributed evenly on the surface of the earth and problems can surface when elemental concentrations are too low (deficiency) or too high (toxicity). The inability of the environment to provide the correct mineral balance can lead to serious health problems. Furthermore, the mineral imbalance in the natural environment can be underlined by geochemical provinces. Thus, the clear demarcation of ‘geochemical provinces’ are also closely linked to the incidence of several regionally distributed diseases. An occurrence of endemic goiter and cretinism has been associated with iodine deficiency in several parts of the globe including India, China, South America and Africa. Selenium deficiency in some parts of China has been related with cases of muscular dystrophy as well as induction of endemic cardiomyopathy. Excess of fluorine in drinking water has been associated with endemic dental and skeletal Fluorosis in several geographical areas including India, China, Africa, Mexico and Chile. Well documented cases of chronic arsenic poisoning from consumption of contaminated drinking water are known in Taiwan, Chile, Argentina, Mexico, China and recently in West Bengal and Bangladesh. Further, the low level of awareness about health hazards due to environmental toxins, general poverty leading to poor nutrition and health status, consumption of food grown in contaminated areas, serious lacking of proper sanitation, pipe-borne clean water and poor implementation of pollution control laws etc. clearly enhances the spread of many diseases and compounds the risks involved.
Infectious diseases in humans are also dramatically affected by the geological environment, albeit indirectly. Geological forces shape the environments in which microbes thrive, sometimes creating opportunities for the emergence of infectious. Atmosphere is a daily host to a variety of particles or aerosols originating from the surface of earth through several geological and anthropogenic processes. Many of these particles are smaller than 2.5 mm making them easy to inhale e.g., alluvial dust, cigarette smoke, coal dust or asbestos affecting our respiratory systems. The trade winds are able to lift these fine mineral particles from soils sometimes laden with bacteria and toxic elements and then carry those particles to great distances around the planet which can impact the health and sustainability of living species. Now a days the satellites tracks and provides an excellent picture of the transport of these dust and other aerosols on a global scale. Geology is the most important factor controlling the source and distribution of radionuclides such as radon, radium, uranium etc. associated with particular types of bedrock and unconsolidated deposits. Inhalation of radon is a severe occupational hazard for uranium miners, commonly resulting in fatal lung cancer. In addition to it, the role of different organic compounds on health is presented by polycyclic aromatic hydrocarbons (PAHs) and pesticides. The PAHs are quite toxic, especially when present in drinking water. One classical example is the case of Balkan Endemic Nephropathy (BEN) which affects the people living in areas of the former Yugoslavia, Romania and Bulgaria. The pesticides are by nature toxic to one or more life forms. Generally pesticides damage the liver and nervous system. Also various microbes and pathogens released during different geological processes have an impact on health. For example, the landslides and the resulting dust clouds generated by the 1994 Northridge earthquake triggered an outbreak of coccidioidomycosis, or valley fever, among residents of the nearby Simi Valley in southern California. The landslide released the soil fungus Coccidioides immitis into dust clouds, exposing people to the fungus which caused valley fever.
Kashmir valley hosts the complete Geological succession ranging in age from Proterozoic to recent interacting with the ambient environment. Concentration of iron and fluoride beyond permissible limits is commonly observed in ground water resources of many parts of the valley. Heavy metal pollution in sulphide mineralised areas of the Valley like Baramulla, Kupwara and Anantnag cannot be ruled out. Vulnerability of Kashmir valley to various natural disasters and progressive mineral based industrialization are also acting great challenges for the health of the region. A thorough assessment of the toxicity posed by bioavailability of geogenic sources is warranted and the real risk to the population needs to be systematically quantified. Geoscientific data so generated can be effectively utilized by medical experts for conducting further epidemiological studies on various health problems. The risks and contaminations once identified can be minimized to safer levels by the established remediation strategies.
Geo-scientists today in association with public health professionals are seriously engaged to understand and address the health problems caused or exacerbated by geological materials and processes. Analytical characterization of naturally occurring trace elements and toxic organic compounds in soil and water is helping to explain patterns of disease. There is a dire need for collection of more information on the sources, distribution, pathways and health effects of potentially harmful substances in the environment in terms of exposure, mixtures of different substances, and dose-response relationships. Furthermore, the merging of physical science and bio-medical databases, development of risk assessment maps, cross training of scientists and application of geo-science tools to other health problems can be practiced. Medical geologists can also help in identifying and ideally controlling various anthropogenic sources of contamination. The aim of research in environmental medicine is not to cure the disease but rather to prevent it. Hence the field of Medical Geology demanding collaboration between the geo-scientists and biomedical researchers offers promise of developing innovative solutions to minimize or prevent exposure to potentially deleterious natural materials and geological processes which can subsequently pave way for a healthy society.
Riyaz Ahmad Mir is a Research Scholar at Indian Institute of Technology Roorkee-247667 with specialization in Remote Sensing and GIS, Glaciology and Climate change. Hr can be reached at firstname.lastname@example.org
M Yaseen Bhat works at the Directorate of Geology & Mining, J&K, Srinagar and can be reached at email@example.com