Lattes are washing out to sea. A new study has found elevated levels of caffeine at several sites in Pacific Ocean waters off the coast of Oregon. The caffeinated sites were not necessarily where researchers expected to find them. The study was conducted by Portland State University master's student Zoe Rodriguez del Rey and her faculty adviser Elise Granek, assistant professor of Environmental Science and Management, in collaboration with Steve Sylvester of Washington State University, Vancouver.
In spring 2010, Rodriguez del Rey and Granek collected and analyzed samples from 14 coastal locations and seven adjacent water bodies as far north as Astoria, Ore., and as far south as Brookings. 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. High levels were also found following a late-season storm of wind and rain that triggered sewer overflows.
The results seem to indicate that wastewater treatment plants are effective at removing caffeine, but that high rainfall and combined sewer overflows flush the caffeine contaminants out to sea.
Granek says, "Our study findings indicate that, contrary to our prediction, the waste water treatment plants are not a major source of caffeine to coastal waters. 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."
Even "elevated levels" of caffeine are measured in nanograms per liter, which the researchers say is well below a lethal dose for marine life. However, an earlier study by Rodriguez del Rey and Granek on intertidal mussels found that caffeine at the levels measured in this current study can still have an effect despite the lower doses
Granek says, "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."
Results of the study were published in the July 2012 issue of the Marine Pollution Bulletin
in an article titled, "Occurrence and concentration of caffeine in Oregon coastal waters."