Changing perceptions of the uses of and hazards linked to the shiny chemical element

At the slightest doubt of a bruise, we would rush to our school infirmary for a dash of a bright red liquid called ‘mercurochrome’. The colour refused to fade from our uniform for weeks despite repeated washes. We flaunted it, our parents hated it; but neither party ever doubted its efficacy. Forty years later today we know that mercurochrome (mercury organohalide), has no antiseptic effect, and that the mercury in it is actually toxic.

Chemistry text books clearly state that metals form strong bonds with oxides, chlorides and sulphides but do not mention a far stronger bond; the one with humans. Despite stone tools being in existence for 2.5 million years, it was only around 9000 B.C. that man started using metal to carve out implements; catapulting the evolution of complex tools faster than we could imagine. The axe evolved into the chain saw, the sling-shot to the AK47.

The glint of gold jewellery identified rich, beautiful women, the sheen of a silver sword defined the strength of strong men. The ‘medical-man’, in contrast, fell in love with a shiny, fluid metal called mercury. From fairness lotion to rejuvenating potion, from antiseptic balm to dental amalgam, from thermometer to sphygmomanometer (BP apparatus), mercury occupied a significant space in the doctor’s bag and medical textbooks.

In history

But as early as 750 B.C., a time when mercury was discovered, the rich and the famous quickly got attracted to this unusual shiny silver-like liquid metal. From Roman palace to Egyptian pyramids, from Chinese gardens to Mayan tombs, mercury was used everywhere as a royal decoration. The Alchemists believed that just by altering the sulphur content of mercury one can change it into another metal; obviously their hope was to end up with tonnes of gold.

On April 21, 1956 at Minamata, Japan, a five-year-old kid was brought to the hospital with complaints of difficulty in walking, talking and convulsions; two days later her younger sister was admitted with the same symptoms. By the end of the month 40 patients were admitted with similar issues. Cats and birds started falling down, struck by convulsions. For chronic patients, skin rashes and kidney and liver failure followed.

The authorities at Minamata notified it as an epidemic. It took another three years and an international expert committee to finally track down the disease as the Minamata Disease, caused by methyl mercury poisoning resulting from industrial waste from a plant named Chisso, manufacturing acetaldehyde. The methyl mercury released by the factory into the Minamata Bay was consumed by fish, which in turn was the staple food of the local community. It is estimated that Minamata disease killed 1,400 people. And it kicked off the worldwide campaign to stop the use of mercury.

As a medicine

For a long time, mercury was used as a medicine; as skin applicant (Calomel, Quick silver) in cosmetics; to relieve fluid retention in heart disease (mercurial diuretics), as a treatment for syphilis (Mercurous chloride) and as antiseptic (mercurochrome). But today mercury has been declared an environmental toxin, which is not degraded even when disposed of.

The United States did it a decade back, Europe followed and the rest of the world slowly crawled out of the blanket of inhibition and banned mercury from clinical use. India has now decided to phase out mercury manometers (BP apparatus) and mercury thermometers.

Many physicians in India are still unable get out of their confidence in the traditional mercury blood pressure apparatus, despite studies showing comparable values with an aneroid ‘spring-based’ and automated digital systems.

The tantalising, shining, liquid metal which spent its life in royal company, promised to turn to gold at the tweak of the alchemist, and expected to cure a variety of illnesses, seems to have miserably failed in its mission, being banned and banished to where it came from, the core of the earth, forever.

So there are no more mercurochrome-stained uniforms to flaunt.

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