(Unfortunately it’s from that class of “today scientists announced to the media” so take it with a pinch of white powder, that they may be extrapolating their findings just a touch, working up justification for something, funding maybe ?)
The clue is the word “only” in the fifth para. Yeah right.
I heard about this on the radio yesterday. I had visions of hundreds of people standing along the banks of the PO and doing their business. I thought “Strange, doesn’t Italy have a sewer system?”
How could this be???
I guess all the water that goes into the sewers ends up in natural water courses somewhere, after “residence time” in the various filters, aerators and digesters in sewage treatment plants ….
So there are two key calculations presumably, how much ends in the Po, from a given catchment and how much of any coke in the incoming sewers ends up as this indicator compound in that water, after the sewage treatment process.
Plenty of room for error and assumption I would have thought ?