The word 'toxicology' is derived from Greek word 'toxikon' meaning poison and 'lotus meaning discourse. Thus it is the science dealing with poisons. Therefore, 'chemical toxicology is the science which deals with study of toxic (poisonous) chemicals and their mode of action.
In this article,we will discuss about the 3 most Dangerous chemicals in the world.
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| Toxic chemicals |
A large number of chemicals are found in the environment. These chemicals may be toxic or non-toxic. The toxic chemicals are discharged by industries into air, water and soil. They get added to the human food chain from the environment. Once they enter our body, they interfere with essential physiological processes, leading to a variety of symptoms of distress, and, if the interference is sufficiently severe, death occurs.
The list of toxic or hazardous substances is very long. In many cases it is not yet clearly known that wheater a particular chemical compound is toxic or otherwise (non-toxic). Some chemicals are very useful and important in our daily life but their non-toxicity has not been proved. In case of certain elements, there is a confusion between the line of essential limit and toxic limit. Such a distinction is artificial and can be misleading.
Many metals listed as environmental dangers are essential dietry trace elements required for normal growth and development of animals and human beings. These elements are Al, Sb, As, Ba, Be, Bi, Cd,, Co, Cu, Ce, In, Pb, Hg, Mo, Ag, Te, Ti, W, U and zn.
The well known most Dangerous chemicals As, Pb and Cd are essential in trace amounts for the healthy growth of animals. The biologically inert element Aluminum if taken in excess causes brain damage, bone disease and anaemia in patients exposed to hemodialysis using water containing 100 to 1000 ppb of Aluminum.
Classification of Toxic Substances:
Some classes of hazardous substances which cause genetic damage, are given below:
1) Physical agents:
Inhalation of small fibres or practices of asbestos causes diseases like asbestosis and mesothelima- a rare form of cancer.
2) Toxic metals:
Metals like Ni, Cd, Hg, and pb which concentrate in the lipid tissues can cause chromosome damages.
3) Oxides of nitrogen:
Oxides like NO2, and N2O3 are extremely carcinogenic as they produce mutagenic nitrosoamines.
4) Organohalogens:
A variety of these compounds are used in nail polish removers, they can cause chromosome damage.
5) Alkylating agents:
Compounds like dialkyl sulphates, epoxides have been known to cause chromosomal aberration in wheat and barley.
6) Aromatic hydrocarbons:
Compounds like benzene, benzpyrine show carcinogenic effects. Dye stuffs derived from these are used in the manufacture of household products such as tissue papers, towels.
7) Anaesthetics:
Frequent use of anaesthetics like Halothane and nitrous oxide cause spontaneous abortions.
8) Air pollutants:
Combustion of coal produces a major air pollutant. It causes respiratory diseses.
9) Food additives:
Fast food items contain substances which are generally recognised as safe. The common fast foods contain coal tar dyes and sugar substitutes.
10) Naturally occurring toxicants:
Fungal, seafood toxins, excess of amino acids occuring in natural food are known to be not only toxic but also carcinogenic.
Toxic chemicals in Air:
Larger population means larger consumption of energy and resources. Hence the quantum of generation of waste products also increases. These waste products lead to problems of air, water and land pollution to the greater extent. World Health Administration and Consumer Product Saftey Commission listed 24 extremely hazardous substances in the atmosphere.
3 Most Dangerous chemicals:
1) Cadmium:
Biochemical Effects of Cadmium:
Cadmium is found in the same group of the periodic table as mercury and zinc, but it's chemical properties are much closer to zinc than to mercury. Cadmium is always found in association with zinc in earth's crust. It is obtained as a by-product of zinc mining and extraction.
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| Itai-Itai disease |
Other sources of cadmium include alkaline batteries, pigments and plating. Due to the similarly with Zn, cadmium is actively taken up by many plants. Most of our cadmium intake is from vegetables and grains in our diet. Smokers get an extra dose because cadmium is concentrated in tobacco leaves.
2) Lead:
Biochemical effects of Lead:
Lead is one of the important, poisonous heavy metals in the environment of human beings. The major source of lead exposure is leaded gasoline. Lead is added in the form of tetraethyl, pb(C2H5)4 or tetramethyl, pb(CH3)4 to gasoline to improve its octane rating by scavenging radicals and inhibiting pre-ignition.
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| Effects of lead |
These compounds are themselves toxic and are readily absorbed through the skin and in the liver where they are converted to trialkyl lead ions, which are neurotoxins. Lead is also emitted during smelting of lead sulphide ore, it can also be released from lead-based solder used in pipe and fitting connections or from pipes themselves, ceramic glaze containing lead, lead storage batteries and many other products that contain lead.
3) Mercury:
Biochemical effects of Mercury:
Mercury was the metal through which we first became aware of a bio-concentration of a metal. It will now serve as a good illustration for the ecological significance of the passage of heavy metals or other long living toxins into the food chain.
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| Effects of Mercury |
Mercury is released into environment as Hg(2) ions through its most common ore, HgS, red cinnabar. Metallic mercury is used in many applications, especially in batteries, switches, lamps and other electrical equipment. Improper use and disposal add to the mercury level.
The use of mercury to extract gold or silver from ores also add to the river has been burn of agriculture which combusts much of the humic material, leaving behind mercury containing residue.
So, this are the most Dangerous chemicals in the world, so stay away from this chemicals as possible as. And live life healthy and longer.