This news comes after the release of a study by Eawag, the Swiss Federal Institute of Aquatic Science and Technology, which found that Swiss wastewater treatment plants are a veritable gold mine. Alongside these riches there are also trace amounts of rare earth metals, such as gadolinium and niobium, flowing out of wastewater treatment plants.
Across the 28 Swiss cantons there is around 3000 kg of silver, 43 kg of gold, 1070 kg of gadolinium and 1500 kg of neodymium lost every year. Switzerland is well known for it’s watchmaking and jewellery industries, and it is also home to many gold refineries, so in many respects these wasted precious metals aren’t much of a surprise.
Any would-be gold prospectors shouldn’t run for their gold pans just yet, as the scientists say these quantities aren’t large enough to justify recollecting the elements.
However, there are a few exceptions. They point out that in areas where watchmaking is a prominent industry (such as the Jura) there are particularly large concentrations of gold. While they point out that “at certain sites in Ticino, concentrations of gold in sewage sludge are sufficiently high for recovery to be potentially worthwhile,” due to the presence of several gold refineries in the canton.
Across the country though, sifting through all that brown stuff isn’t considered particularly worthwhile. Which probably goes without saying.
Fortunately, the elements that are being released aren’t considered to be of “ecotoxicological concern”. But this comes with a caveat: we aren’t really sure about the effects that some “emerging trace elements” can have on the environment. So this assessment probably needs some more work.
Next time you happen upon a Swiss sewage treatment plant, you may well see a glint of gold among all that sludge. But we don’t suggest you dive in after it.