Now let us discuss the harmful effects of some specific particulates, especially the dusts containing metallic particles. Metals such as zinc, mercury, lead, copper, cadmium, etc. Are released into the atmosphere during isolation and refining of these metals and also through use of pesticides. Although these metals are present in small concentrations, some of them are very harmful to living organisms.
Lead Poisoning
The major sources of lead particles in air are:
- Tetraethyl lead is used us antiknock compound in gasoline. Therefore, automobile exhausts contain some lead salts, which are released into air.
- Some industries release dust containing lead particles. For example: The industries engaged in manufacture of lead-storage batteries, lead paints, lead alloys, lead smelting, etc. released dust containing lead particles.
- Lead-arsenic compounds are used as insecticides to dust plants. They are also responsible for lead particles in the air.
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The excessive accumulation of lead in the human body results in lead poisoning. Even 0.2 ppm of lead concentration may metabolic disturbances. Some of the harmful effects of lead poisoning are:
- Lead poisoning interfaces with development and maturation of red blood corpuscles (RBC) in the human body and hence causes anaemia. Prolonged exposure to lead leads to stippled red blood cells.
- Lead is bound with cellular enzymes and disrupts the functioning of cells organs of muscular, circulatory and nervous systems.
- It causes coagulation of proteins.
- It may damage liver, kidney and intestine.
- Lead poisoning induces abnormalities in fertility and pregnancy.
- Lead poisoning is treated by using calcium disodium salt of EDTA.
Mercury Poisoning:
Mercury metal is highly poisonous. Mercury is quite volatile and is easily absorbed through the skin. The major sources of mercury as pollutant are:
- Industrial wastes containing mercury and its salts.
- Use of some fungicides, which contain mercury.
- Mining and metallurgy of mercury.
Mercury can also be a health hazard when it is present in food. Mercury enters the food chain through small organisms and accumulates as the food chain progresses. Mercury poisoning causes a disease called minamata in human beings. The disease was first observed in Japanese fisherman who consumed fish containing high concentrations of mercury. The symptoms of mercury poisoning are sponginess of gums, anaemia, muscular weakness, mental retardation and paralysis.
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Asbestosis:
Asbestosis dust is also a serious health hazard. Workers exposed to this type of dust suffer from a disease called asbestosis and lung cancer. Asbestosis a disease related with lungs and causes respiratory complications. The major sources of asbestos are the industries handling asbestos. These are the industries engaged in the manufacture of asbestos sheets, fire-proof fabrics, insulting materials, etc.