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THEY DRINK an awful lot of coffee in Seattle—so much so that an
investigation into local water pollution has literally gone down the drain.

Water quality researchers had planned to use caffeine—which doesn’t
occur naturally in water but gets into sewage through people’s urine—as a
tracer to determine where treated sewage flows when it enters the sea at Puget
Sound. But after initial tests the idea had to be abandoned.

The problem was the number of pavement cafes selling Seattle’s favourite
drink. At the end of the day, waiters throw the dregs down the drains, which
lead…

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