Your coffee-drinking habits may be harming the environment, according to a new US study which found that caffeine gets expelled with our urine and enters the water bodies through sewage systems, posing a threat to wildlife.
Researchers from San Diego's Regional Water Quality Control Board in the US found caffeine in water sampled from remote streams far from urban areas and sewer systems.
They analysed about 100 water samples over a seven-year period. They came from a range of sites encompassing raw sewage and treated wastewater in urban areas, as well as streams in remote open-space areas where there is no human development.
They team found that samples from urban areas tested positive for caffeine. Samples from untreated sewage contained between 0.052 and 8.5 microgrammes per litre, while those taken near active septic systems ranged from 0.029 to 1.19 microgrammes per litre.
More than one-third of the samples from open-space areas tested positive for caffeine, researchers said.
This suggests visitors in these areas may not be practising good habits, whether by urinating too close to streams or leaving waste behind, researchers said.
The results also suggest that other contaminants found in human waste, such as pharmaceuticals and pathogens, could be polluting these areas, they said.
"We were completely shocked by the result. The areas known for high recreational use like fishing, horseback riding, hiking, camping were the ones that had caffeine hits," Carey Nagoda from Regional Water Quality Control Board was quoted as saying by 'UPI'.
An earlier study had found that near-shore mussels were forced to use energy to make a protein that protects its DNA when exposed to low levels of caffeine.
However, those found in high level areas stopped producing the protein and were at risk of genetic mutation.
"They get so stressed out at a cellular level that they can't protect their DNA with this protein," researchers said.