In epidemiology, environmental diseases are diseases that can be directly attributed to environmental factors. Apart from the true monogenic genetic disorders, environmental diseases may determine the development of disease in those genetically predisposed to a particular condition. Stress, physical and mental abuse, diet, exposure to toxins, pathogens, radiation, and chemicals found in almost all personal care products and household cleaners are possible causes of a large segment of non-hereditary disease. If a disease process is concluded to be the result of a combination of genetic and environmental factor influences, its etiological origin can be referred to as having a multifactorial pattern.
There are many different types of environmental disease including:
Disease caused by exposure to toxic or irritant chemicals in the environment such as toxic metals
Disease caused by physical factors in the environment, such as skin cancer caused by excessive exposure to ultraviolet radiation in sunlight
Lifestyle disease such as cardiovascular disease, diseases caused by substance abuse such as alcoholism, and smoking-related disease
1. Environmental Diseases vs. Pollution-Related Diseases
Environmental diseases are a direct result from the environment. Meanwhile, pollution-related diseases are attributed to exposure to toxins in the air, water, and soil. Therefore all pollution-related disease are environmental diseases, but not all environmental diseases are pollution-related diseases.
2.1. Chemicals Metals
Poisoning by lead and mercury has been known since antiquity. Other toxic metals or metals that are known to evoke adverse immune reactions are arsenic, phosphorus, zinc, beryllium, cadmium, chromium, manganese, nickel, cobalt, osmium, platinum, selenium, tellurium, thallium, uranium, and vanadium.
2.2. Chemicals Halogens
There are many other diseases likely to have been caused by common anions found in natural drinking water. Fluoride is one of the most common found in drier climates where the geology favors release of fluoride ions to soil as the rocks decompose. In Sri Lanka, 90% of the country is underlain by crystalline metamorphic rocks of which most carry mica as a major mineral. Mica carries fluoride in their structure and releases to soil when decomposes. In the dry and arid climates, fluoride concentrates on top soil and slowly dissolves in shallow groundwater. This has been the cause of high fluoride levels in drinking water where the majority of the rural Sri Lankans obtain their drinking water from backyard wells. High fluoride in drinking water has caused a high incidence of fluorosis among dry zone population in Sri Lanka. However, in the wet zone, high rainfall effectively removes fluoride from soils where no fluorosis is evident. In some parts of Sri Lanka iodine deficiency has also been noted which has been identified as a result of iodine fixation by hydrated iron oxide found in lateritic soils in wet coastal lowlands.
2.3. Chemicals Organic compounds
Additionally, there are environmental diseases caused by the aromatic carbon compounds including: benzene, hexachlorocyclohexane, toluene diisocyanate, phenol, pentachlorophenol, quinone and hydroquinone.
Also included are the aromatic nitro-, amino-, and pyridilium-deratives: nitrobenzene, dinitrobenzene, trinitrotoluene, paramethylaminophenol sulfate Metol, dinitro-ortho-cresol, aniline, trinitrophenylmethylnitramine tetryl, hexanitrodiphenylamine aurantia, phenylenediamines, and paraquat.
The aliphatic carbon compounds can also cause environmental disease. Included in these are methanol, nitroglycerine, nitrocellulose, dimethylnitrosamine, and the halogenated hydrocarbons: methyl chloride, methyl bromide, trichloroethylene, carbon tetrachloride, and the chlorinated naphthalenes. Also included are glycols: ethylene chlorhydrin and diethylene dioxide as well as carbon disulfide, acrylonitrile, acrylamide, and vinyl chloride.
2.4. Chemicals Noxious gases
Noxious gases can be categorized as: Simple asphyxiants, chemical asphyxiants, and irritant gases. The simple asphixiants are nitrogen, methane, and carbon dioxide. The chemical asphyxiants are carbon monoxide, sulfuretted hydrogen and hydrogen cyanide.
The irritant gases are sulfur dioxide, ammonia, nitrogen dioxide, chlorine, phosgene, and fluorine and its compounds, which include luroine and hydrofluoric acid, fluorspar, fluorapatite, cryolite, and organic fluorine compounds.
3. Categorization and surveillance
The U.S. Coast Guard has developed a Coast Guard-wide comprehensive system for surveillance of workplace diseases.
The American Medical Associations fifth edition of the Current Medical Information and Terminology CMIT was used as a reference to expand the basic list of 50 Sentinel Health Events Occupational published by the National Institute for Occupational Health and Safety NIOSH, September, 1983.