There are, apparently, lots of useful heavy metals getting flushed down the drain, on a level equivalent to some commercial mines:
A previous study, by Arizona State University, estimated that a city of 1 million inhabitants flushes around $13m (£8.7m) worth of precious metals down toilets and sewer drains each year.
In findings presented on Monday at the 249th National Meeting & Exposition of the American Chemical Society in Denver, the scientists showed that the levels of the precious levels were comparable with those found in some commercial mines.
The eight-year study, which involved monthly testing of treated sewage samples, found that 1kg of sludge contains around 0.4mg gold, 28mg of silver, 638mg copper and 49mg vanadium.
I swear that in my lifetime that we'll start mining landfill for rare metals
Oh yeah, for sure. I have thought about that a lot. Just think of all the metals in landfill from the era before anybody bothered to recycle anything.
I'd much prefer mining landfill to the current plans of mining the deep sea.