Scientists reported that about millions of dollars worth of gold and silver float through Switzerland's sewer systems every year.
However, besides for gold, the report shows, the Swiss sewage becomes more and more crowded as the years go by, because annually almost 3.000 kilograms of silver are being thrown away.
But before people start hunting in their drains for jewellery, the government study said the tiny particles were likely to be mostly from the watchmaking, pharmaceuticals and chemical industries, which use the metals in their products and processes.
That's over $2.25 million in gold and $2.12 million in silver, researchers report.
Apart from gold and silver, several other rare earth metals such as gadolinium and heavy metal niobium were also found in the Swiss wastewater.
"Overall, however, according to the researchers, the recovery of metals from wastewater or sludge is scarcely worthwhile at present, either financially or in terms of the amounts which could be extracted", the report says.
In some areas of Ticino in southern Switzerland, where there are several gold refineries, "concentrations of gold in sewage sludge are sufficiently high for recovery to be potentially worthwhile", the study says. This was the only region where it might make sense to recover the metals, Vriens said.
The discovery of sewer gold in Switzerland has social media talking.
Scientists at the Swiss Federal Institute aquanaute and technology has estimated that approximately 43 kilograms of gold, worth about $ 1.8 million annually passes through the waste water.
The Swiss metal concentrations complied with regulations and were removed before humans drank the water again, the study said.