Caffeine tracks contamination

Coffee dregs label household pollution in lakes and oceans.
20 January 2003
HELEN PEARSON

Each person discards the equivalent of a tenth of a cup of coffee per day

Tell-tale traces of caffeine can expose the level of household waste gushing into lakes and oceans, researchers have shown.

Caffeine is an ideal chemical indicator to distinguish domestic water flushed down sinks and toilets from agricultural effluent, say Ignaz Buerge and his colleagues of the Swiss Federal Research Station in Wädenswil.

Copious amounts of caffeine end up down the drain in coffee-cup dregs and urine. Although sewage treatment removes up to 99.9% of it, caffeine is so abundant and chemically stable that it remains detectable.

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