As a kid, I'd flush things that I wasn't supposed to down the toilet as gifts for the Teenage Mutant Ninja Turtles. So I can understand how things of value make their way into the sewage system, but never would I have thought of the sewer as a place to find gold and other precious metals.
Turns out that there's a goldmine running underneath the streets of Switzerland in the sewage system. Scientists have determined that there is about $1.5 million worth of gold and silver that end up in the sewer every year.
Before you make your way down a stinky manhole to claim your fortune, it's important to know that there isn't enough down there for you to collect to make it worth your while. Not is there only gold and silver in the sewer, but there are also other precious metals found there.
Under commission by the Swiss Office for the Environment, 64 wastewater treatment plants around the country have been analyzed by the team from the Swiss Federal Institute of Aquatic Science and Technology (Eawag). They found that 95 pounds of gold, 6,614 pounds of silver, 2,359 pounds of gadolinium, 3,307 pounds of neodymium; and 330 pounds of ytterbium enter the sewer per year.
Some of the metals are making their way into the wastewater from households and other normal human activities like washing cars, but they are primarily making their way into the sewage system as a result of industrial activity.
Since wastewater is often used for farming irrigation, it's important to know that the presence of metals in water can alter its composition and affect the soil that it is used on. Some of these elements are toxic and using it on consumable products could be devastating. Fortunately, Eawag found that the metals in Switzerland's sewage aren't a threat to the environment.