A study at the University of Montreal’s Department of Chemistry indicates that traces of caffeine are a useful barometer used to determine contamination of our water in sewers.
The project, lead by Professor Sébastien Sauvé, examined water samples from storm water collection points across Montreal in June and October 2008, during dry and wet weather each of those months.
“E coli bacteria is commonly used to evaluate and regulate the levels of fecal pollution of our water from storm water discharge, but because storm sewers systems collect surface runoff, non-human sources can contribute significantly to the levels that are observed,” Sauvé told science journal Chemosphere. “Our study has determined that there is a strong correlation between the levels of caffeine in water and the level of bacteria, and that chemists can therefore use caffeine levels as an indicator of pollution due to sewerage systems.”
Water samples taken from streams, brooks and storm sewer outfall pipes that collect storm waters were analyzed for caffeine, fecal coliforms, and a third suspected indicator, carbamazepine. All the samples contained various concentrations of these contaminants, suggesting contamination is extremely common in urban environments.
Fecal coliforms aren’t always easy to analyze, so Sauvé and his colleagues searched for other compounds that might stand in as a red flag that these fecal coliforms are present.
Caffeine can degrade within a few weeks to up to three months in the environment and is widely consumed by a large number of people. The presence of abnormal caffeine levels is a good indicator of human sewage contamination, as agriculture and industry do not tend to release caffeine into the environment. The study also discovered that the data suggests that Montreal’s storm-water collection system is contaminated by domestic sewer wastewater.
About three percent of caffeine from coffee, chocolate, tea and energy drinks ends up in the sewer system, excreted through human urine. In urban areas where the only source of caffeine is human urine, high levels of the compound in rivers or other bodies of water (where human urine and feces should not be present) are signs of contamination by fecal coliform bacteria, the new research finds.
“If fecal coliforms come from human sewage, they will come with caffeine,”Sauvé said. “So if we find caffeine, that means it came from sanitary contamination.”
On the other hand, the researchers observed high levels of fecal coliforms but little or no caffeine in some of the samples, which is attributed to urban wildlife.
“This data reveals that any water sample containing more than the equivalent of 10 cups of coffee diluted in an Olympic-size swimming pool is definitely contaminated with fecal coliforms,” Sauvé said. “A caffeine sampling program would be relatively easy to implement and might provide a useful tool to identify sanitary contamination sources and help reduce surface water contamination within an urban watershed.”
Jeff Moore is a data reporter at The Daily Reporter. He quit caffeine last week.