Researchers from the government's institute of aquatic science and technology, EAWAG found three tons of silver and 43 kilograms of gold in Swiss sewage, worth a combined 3 million Swiss Francs (€2.6 million, $3.1 million).
However, the scientists were quick to point out that the particles they found are not even visible in most cases, so there is no point in digging for gold yourself.
Read more: From noxious sludge to clean water
"The levels of gold or silver were very small, in the micrograms, or even nanograms, but when you add them up it's pretty substantial," Bas Vriens, who authored the first ever report of this kind by Swiss authorities, said. The report was commissioned by the government.
They also did not find any rings or other jewelry – in fact the tiny flecks of gold and silver are most likely waste products from watchmakers, pharmaceutical firms and chemical companies.
Gold to be retrieved?
Higher levels of gold were found in the western Swiss region of Jura, believed to be linked to watchmakers who use the precious metal to decorate their expensive timepieces. There were also high concentrations in the Ticino area, which is home to gold refineries.
The researchers are now looking into finding a cost-effective way to retrieve some of the gold, especially in the Ticino region.
Researchers also found high levels of other metals and rare earths in the sludge, such as tantalum and germanium – both of which are used in the high-tech and pharmaceuticals sectors.
The report stresses that Swiss tap water remains unaffected.
ng/kms (Reuters, dpa)