A new NOAA-funded study does reveal is that traces of caffeine in Pacific Northwest waters and point to a likely source of the stimulant: septic tanks and sewer overflows.
This research, the first to look at caffeine contamination off the Oregon coast, found elevated levels of caffeine at several sites in Pacific Ocean waters off the coast of Oregon—though not necessarily where researchers expected.
The study found high caffeine levels near large population centers like Astoria/Warrenton and Coos Bay. They also found that caffeine levels spiked following a late-season storm of wind and rain that triggered sewer overflows.
“Our study findings indicate that, contrary to our prediction, the waste water treatment plants are not a major source of caffeine to coastal waters,” said Elise Granek, assistant professor of environmental science and management at Portland State University. “However, onsite waste disposal systems may be a big contributor of contaminants to Oregon’s coastal ocean and need to be better studied to fully understand their contribution to pollution of ocean waters.”
Caffeine is found in many food and beverage products as well as some pharmaceuticals, and caffeine in waterways is directly related to human activity. Although many plant species produce caffeine, there are no natural sources of the substance in the Pacific Northwest leading us to the question “Is coffee from Starbucks and other Pacific Northwest coffee shops polluting the ocean?” The answer is, indirectly, maybe, but the problem is more accurately attributed to the need for better sewage treatment plants.