Tuesday, 23 June 2015

Lead - All you need to know!

Why in news?
Mainly because of the Maggi issue.

About Lead



Source: The Times of India



Some notable things about lead:

  • This toxic heavy metal and its salts have no known beneficial biological function — they have only deleterious effects
  • Particles measuring less than 10 microns in diameter are directly absorbed by our respiratory system. Hence, one of the main pathways of lead into humans is the inhalation of contaminated air.
    • Other pathways: Skin, direct absorption through digestive system
  • It is important to note that there is neither a placental barrier nor a blood-brain barrier for lead. 
  • Lead replaces minerals, notably iron and calcium, in the body and prevents haemoglobin formation, resulting in anaemia.
  • The wordwide annual production of lead today amounts to 50 lakh tonnes; it is used in solder, paint and even food colouring. By now, lead has accumulated in significant quantities in human bodies and the environment. But the major culprit in the spread of lead is the anti-knock additive to the automobile fuel, tetraethyl lead (TEL). 
    • It was definitely established that alcohol can be blended with gasoline to produce a suitable motor fuel. But alcohol cannot be patented and cannot bring large profits to companies. So, all discussion of its potential was deliberately suppressed, and TEL pushed with vigour.
[Sources: Indian Express, The Hindu]

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