According to a new study, our daily caffeine consumption can offer an indication of city sewer leaks and overflows.
According to the study, about 3% of caffeine from coffee, tea, chocolate and energy drinks gets into the sewer system through human urine. In urban areas where human urine is the only caffeine source, high levels of caffeine in bodies of water where it should not be present may indicate signs of contamination by fecal coliform bacteria.
“If fecal coliforms come from human sewage, they will come with caffeine,” says study researcher Sébastien Sauvé, an environmental chemist at the University of Montreal. “So if we find caffeine, that means it came from sanitary contamination.”
Fecal coliform bacteria can also turn up in waterways via animal feces, so having caffeine is an important indicator of contamination by humans, proving there are deeper issues with the sewer than too many animals taking care of business.
Researchers took 120 water samples on the Island of Montreal, during both dry and wet weather periods. Since fecal coliforms aren’t always easy to analyze or detect, they tested for caffeine and carbamazepine, an anti-seizure medication that degrades very slowly.
The carbamazepine and fecal coliform counts were not linked, particularly due to small numbers of people taking the drug. However, with the number of caffeine consumers, researchers found that if caffeine appeared in the water at about the equivalent of four cups of coffee in an Olympic-size swimming pool, fecal coliform levels were always above 200 units per 100 milliliters of water. This number is deemed unsafe for swimming or bathing in Canada. The U.S. Environmental Protection Agency counts 235 units per 100 milliliters to be unsafe.
Caffeine isn’t a perfect indicator of contamination, but the marker could help to indicate to professionals when sewer repairs are necessary.
So now your daily caffeine intake is useful for something other than keeping you on the go!