Elements

Mercury is beautiful, yet deadly poisonous. Known as quicksilver, the Minamata international treaty aims to phase its use out completely. But how will the ban on element 80 affect artisanal gold miners? Or coal-fired power stations? And why does so much of this liquid metal end up in tuna and swordfish? (Picture: Ghanaian artisanal miner holds mercury in his hand; Credit: Matt Davies/BBC)

Light, strong and flexible, aluminium is used in drinks cans, window frames, aircraft and packaging. Ubiqitous today, why was it valued more highly than gold 150 years ago? Is it better to recycle this metal, or spend vast amounts of energy creating more of it from scratch? And why is Jaguar Landrover teaching robots to rivet?

The second most abundant element in the universe, helium is rare on Earth. In liquid form it is used as a coolant in super conducting magnets in MRI scanners – so should this rare element be used in something as frivolous as party balloons? And what happens to the helium when that balloon inevitably escapes the clutch of a small child? (Picture: US National Helium Reserve; Credit: Jonny Dymond/BBC)

Phosphorus is essential for life. Our crops would not grow without phosphate fertiliser. So should we worry that we may be frittering the stuff away? Or that most of the world's remaining reserves are controlled by one country? Or that our phosphorus-rich waste may be asphyxiating fish? The possible solution to these problems stinks.

The periodic table provides an entirely new perspective on how the global economy works, as we discover in the first part of a new series about the chemical elements. A mining engineer working with Rio Tinto explains the geological processes that took millions of years to create the useful concentrations of these fundamental building blocks, and the often brutal process of extracting them. We hear about a project to dissect mobile phones in order to highlight the disturbing stories behind some of the 40 elements they contain. And we take a guided tour of the world’s main trading forum for eleven of the biggest elements – the London Metals Exchange.