A taste of heavy metal

Education Services / L’équipe des services d’éducation
26 January 2012

What do bands like Black Sabbath and Metallica have in common? Well, as any music lover knows, they are both famous heavy metal bands. But the term “heavy metal” doesn’t just relate to the Ozzy Osbourne’s of the world. It also refers to an important group of chemical elements which can drastically affect our health and environment.

By definition, a heavy metal is any chemical substance that has a high density (specific gravity greater than five) and is highly poisonous even at very low concentrations. Examples of some common heavy metals include mercury (Hg), lead (Pb), arsenic (As) and chromium (Cr), to name just a few.

Did you know? Some chemists and scientists prefer to use the phrase“Toxic Metal” over “Heavy Metal” based on how harmful these substances are.

Generally speaking, heavy metals deserve their bad “rap”because they are some of the most dangerous contaminants in our environment today. Why are they so harmful? Heavy metals tend to bioaccumulate within organisms. Bioaccumulation describes the phenomenon whereby toxic substances build up inside an organism at a rate faster than they can be broken down. Over time, the concentration of heavy metals can increase in the bodies of animals high on the food chain (i.e. eagles, bears and humans) as a result of eating smaller animals or organisms contaminated with heavy metals.Larger animals, including humans, can end up having more than a thousand times the amount of heavy metal contamination than their smaller counterparts.

Did you know? Heavy metal poisoning can cause cancer, learning disorders,skin discoloration (argyria), liver failure, kidney disease, chronic neurological disorders, heart failure, and even death.

But heavy metals aren’t always bad for our health. For example, we need iron so that hemoglobin in our blood can carry oxygen.Vitamin B-12 is a cobalt-based complex that is critical for brain and nerve development. Gold salts are valuable medicines used to treat rheumatoid arthritis. Drugs like cis-platinum, carboplatin, and ferrocenyl tamoxifen are highly effective anti-cancer agents. In fact, heavy metals are currently being investigated for their use as medicinal agents in nanotechnology.

Did you know? Hospitals use minute amounts of heavy metals such as barium, technetium, cadmium, and thallium as radionuclides when they perform X-rays because they can be “traced” through the human body to help diagnose disease.

So the next time you listen to some “heavy metal”, remember that it is so much more than just music to your ears.

Learn more!

Heavy Metals in Cosmetics – Health Canada

Heavy Metal Coatings in Children's Jewelry – Health Canada

What is mercury poisoning?

Article first published April 8, 2011.

Article revised on July 14, 2014.

Education Services / L’équipe des services d’éducation

This content is provided through Let's Talk Science's Education Services team.

Ce contenu est fourni par l'équipe des services d'éducation de Parlons sciences.

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