The New Straits Times, July 29, 2001
By Professor Dzulkifli Abdul Razak
When one talks of heavy metals nowadays, names like Black Metal, Trash Metal and Black Tooth come to mind. Hardly a day passed in the last few weeks that such names did not appear in the news. To most, however, heavy metal is nothing more than a brand of loud music.
One heavy metal website in fact declares: "Heavy Metal is the louder (sic) and most powerful music in the world. Listen and worship it, or you aren't worth enough to live". In contrast, there are those who want heavy music to be banned.
But not all heavy metal can be listened to, still less is it worth worshipping, and most certainly it should be banned. These are the class of chemical elements also known as heavy metals which can actually poison the body.
Thus while heavy metals are currently attracting much attention, it is probably an opportune time to introduce the lesser known chemical dimensions of heavy metals, the ones that are controversial.
Though some are important to health, other chemical types of heavy metal can be hazardous to human health. Examples, of the latter are arsenic, cadmium, lead and mercury.
On the other hand, copper, iron, manganese and zinc, are required by the body, albeit in small quantities. Better known as "essential minerals" they are normally found in food. But in larger amounts they too can be as toxic as heavy metal, tending to accumulate in the body's soft tissues.
Heavy metal substances are generally prevalent in the environment. They may enter the body through food, water, air or by absorption through the skin. Some people may come in contact with heavy metals at workplace - industrial, manufacturing, and agricultural sectors.
As an example, lead is found in leaded petrol, vehicle exhaust, lead water pipes and leaded paints, including toys.
Mercury is found in industrial and agricultural wastes as well as contaminant in food such as fish. Amalgam dental filling also contains mercury (see Poison Control May 13).
Once in the body, heavy metals can interfere with normal organ system functions by competing with and displacing important elements such as calcium, copper and magnesium.
Toxic symptoms depend on the types, nature and quantity involved. It also depends on how they are introduced into the body, for example, ingested, inhaled or through skin contact. Mercury specifically can cause skin burns, while the inhaled vapour can cause severe inflammation of the lungs.
More alarming still is that heavy metals like lead can impair cognitive, motor and languages skills among school-going children. The IQ may be lowered over time. At more toxic levels it can result in insomnia, headache, mania, and convulsions.
The usual way of removing heavy metal from the body is to employ chelating agents given orally, intramuscularly or intravenously. Examples are edetate calcium disodium, dimercaprol (BAL), and penicilamine often used clinically.
The chelating agent traps and binds the metal in the body's tissues, forming a complex, which is then released from the tissue and travels in the bloodstream. The complex is filtered out of the blood by the kidneys and excreted in the urine.
But it can only stop further effects of the poisoning; it cannot reverse the damage already sustained. They are more effective in treating lead, mercury and arsenic poisoning, but not for cadmium.
In summary, heavy metals, be it the music or chemical substance, should be properly used and handled. Otherwise it can cause many undesirable results, poisoning not only the body but also the mind.
Recommended websites: http://www.emedicine.com/EMERG/topic237.htm
