Biochem Blogs

Biochemistry blog, science writing

Cadmium: toxic to mammals, harmless to a bacterium, helpful to an alga

Joe Magliocca

Joe MaglioccaI'm on ScienceSeeker-Microscope

Heavy metal poisoning is a major health concern across the world. Heavy metal ions frequently leak into the environment from industrial waste causing multiple health problems in humans, animals, and other organisms. While there is no universally accepted definition of what elements are heavy metals, the definition I find most useful includes the metal rubidium and all metals heavier than it.  These metals have large atomic masses, and aside from molybdenum (and possibly tungsten), have no essential biological function; they only interfere with other biological functions.

One heavy metal of significant concern is element 48, cadmium. This element is mostly found in nature as an impurity in zinc ore, but small amounts are scattered throughout soil, seawater, coal, and other mineral deposits. It first became known as an environmental and medical hazard when a disease known as “itai-itai” (literally “it hurts-it hurts”) appeared around the city of Toyama, Japan between the Russo-Japanese war and World War II (roughly 1905-1945). This city was a major center for zinc mining, and the cadmium waste from this process was found to be the cause of the disease.

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