Selenium is trace element and is needed by our body in minute’s doses. Its deficiency and toxicity may cause life threatening diseases like ischemic heart disease and Aids.
Selenium like Arsenic and Sulphur is great pollutant of soil. The poisoning of these trace elements causes many an undesired effects on animals and humans. The high concentration of these trace elements in blood causes toxic effects that are antagonistic to the cell formation and growth of body. Their deficiency especially of selenium can lead to many health related issues and problems. Selenium is a metalloid with its chemical properties some what similar
to Sulphur Metalloid is an element that has some characteristics of a metal and some of a non-metal
It is a trace mineral that plays a significant role in the maintenance of human immune system and its homoeostasis. Selenium is not essential for the growth of plants and is not found in their chemical structure and composition. Plants growing on selenium rich soils accumulate it in their leaves and other soft parts. When cows, buffaloes and other domestic animals feed on such vegetation than excess of selenium in their blood leads to selenium toxicity and poisoning causing loss of hair and hooves and muscles. The high concentration of selenium in humans, wild life and domestic animals causes many health problems and it is very hazardous to certain animal survival conditions. In some parts of the world it is very deficient but in others it is more than the desired level. Selenium is very toxic in certain parts of Punjab It is very highly concentrated in soil especially the soil of Hoshiarpur district.
Selenium occurs along with sulfur in coal and coal based thermal plants. These thermal plants release selenium as a compound as selenium oxide into the atmosphere and solid waste in the form of fly ash. So the thermal plants are great pollution causing agents and source of atmospheric pollution in Punjab, especially in Roper and Bhatinda districts. In addition to that some soils also contain excess selenium, released from natural degradation of seleniferrous rocks. The soils containing five mg/kg selenium or above are said to be toxic or selendiferoussoils. It is present in soils and in water in insoluble
Selenium compounds
Selenium exists in different compounds forms in the soil and nature. Its compound formation depends on the ph value of the soils. The high ph soils contain selenate form of selenium while low ph soils contain biselenite compounds. The most vegetative crops that are prone to its high concentration are: wheat, sugarcane, Potatoes, radish, carrot, turnips and tomatoes. Garlic is said to be accumulating highest concentration of selenium so garlic can be both health booster and health hazard.
Dual nature
Selenium has dual nature. It is very helpful on the one side and very toxic on the other. In some conditions it is every essential and in others it is harmful and toxic. It is very essential in low concentration to animal life but if ingested in larger quantities and high concentration it causes diseases such as cancer, muscular dystrophy and many cardio vascular diseases. Scientists have confirmed a correlation between low level of selenium or its deficiency and ischemic heart diseases. The deficiency of selenium may trigger the development of HIV virus in human body. It is said that Aids causing HIV virus contains at least four seleno proteins. These seleno proteins deplete the selenium from the body of the Aids patient making him prone to infectious diseases and full blown Aids. Similarly animals thriving on rich selenium vegetations show varied kinds of symptoms like development of cracks on hooves, peeling of the horns loss of hair from the body parts, loss of tail and its degeneration, detachment of hooves etc. In animals it is deposited in blood, hooves and hair causing their speedy loss. Selenium is trace element for humans too. It is essential part or the enzyme peroxidase which plays an integral part in protecting cell membrane. The daily intake of selenium of 50-200micrograms is advised by nutritionists. The deficiency symptoms began to surface if this concentration or intake of selenium is lower than 10 micrograms or less per day.