Elevated levels of caffeine found at several sites in Pacific Ocean waters off the coast of Oregon. A study developed and conducted at Portland State University collected and analyzed samples from 14 coastal locations and seven adjacent water bodies as far north as Astoria, Oregon., and as far south as Brookings.
Caffeine is found in many food and beverage products as well as some pharmaceuticals, and caffeine pollution is directly related to human activity (although many plant species produce caffeine, there are no natural sources of the substance in the Northwest). The presence of caffeine may also signal additional anthropogenic pollution, such as pesticides, pharmaceuticals and other contaminants.
Locations were identified as potentially polluted if they were near wastewater treatment plants, large population centers or rivers and streams emptying into the ocean.
The study found high caffeine levels near Carl Washburne State Park (Florence, Ore.) and Cape Lookout, two areas not near the potential pollution sources, yet low levels of caffeine near large population centers like Astoria/Warrenton and Coos Bay.
Our study findings indicate that, contrary to our prediction, the waste water treatment plants are not a major source of caffeine to coastal waters
High levels were also found following a late-season storm of wind and rain that triggered sewer overflows.
"We humans drink caffeinated beverages because caffeine has a biological effect on us—so it isn't too surprising that caffeine affects other animals, too," says G Elise Granek, assistant professor of Environmental Science and Management.
Previous studies have found caffeine in other bodies of water around the world, including the North Sea, the Mediterranean, Puget Sound, Boston Harbor, and Sarasota Bay, Fla.