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Simon Goodman
Griesheim, Germany
Which elements could be “deleted” without any ill effect on our lives depends on whether you mean we human animals, all life forms on the planet or us as part of an industrialised society.
As humans, we can, of course, discard all transuranic elements, created since 1944. The lanthanides (elements 57 – 71) have no known biological function, and the noble gases in period VIIIa are chemically inert.
Biology wouldn’t be here without hydrogen, nitrogen, carbon, oxygen, sulphur and phosphorus, as they are major components of biological macromolecules like proteins, nucleic acids, sugars and fats. The ions of the metals sodium and potassium are crucial for generating potential across cell membranes. Magnesium is needed for energy functions, and calcium for structures in bone and teeth.
Many metals are critical in trace amounts in various human enzymes. These include zinc and copper (e.g. in superoxide dismutase), molybdenum, manganese, chromium and cobalt (in vitamin B12). Fluorine may also be a necessary trace element. Small amounts of arsenic and vanadium are needed by chickens, rats, goats and sheep, but have no confirmed role in humans. In plants and microorganisms, a few other elements, including silicon, boron and bromine, may be vital.
Industrialised society uses much of the rest of the periodic table in amounts ranging from billions of tonnes to micrograms worldwide each year. If you count carbon, then coal alone is around 9 billion tonnes of fairly pure carbon.
We use tens of millions of tonnes per year of “structural” metals like copper, iron, aluminium, chromium and nickel for electrical and building applications.
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