In recent months, stories about sewers getting clogged have made international headlines. For example, a so-called "fatberg," a mass of grease and diapers, clogged London's sewers. A new study has found stranger materials in a wastewater system: large amounts of rare and precious metals. Researchers examined 64 wastewater treatment centers across Switzerland. A government press release says it was the first study on trace elements in wastewater in an industrialized country. The researchers found 3000 kg of silver and 43 kilograms of gold in effluent and sludge from the centers. The value of the materials was somewhere around $3.1 million dollars. The silver and gold were in the form of tiny particles. The researchers said the particles were most likely released during manufacturing of chemicals, pharmaceuticals, or watches.