Traces of the popular beverage in waterways and oceans can be an indicator of other anthropogenic pollution
By Summit Voice
SUMMIT COUNTY — Scientists on the lookout for all sorts of water pollution have found elevated levels of caffeine in unexpected locations in the Pacific Ocean off the coast of Oregon.
While caffeine may not be the biggest environmental problem, the researchers explained the presence of caffeine can signal additional anthropogenic pollution, such as pesticides and pharmaceuticals.
The presence of caffeine can also provide a pathway to understand the effectiveness of wastewater treatment systems. 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.
The study by Portland State University’s Zoe Rodriguez del Rey and her faculty adviser Elise Granek is the first to look at caffeine pollution off the Oregon coast. Rodriguez del Rey is a master’s student and Granek is an assistant professor of Environmental Science and Management. They collaborated with Steve Sylvester of Washington State University, Vancouver.
“Our study findings indicate that, contrary to our prediction, the waste water treatment plants are not a major source of caffeine to coastal waters,” says Granek. “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.”
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 contaminants out to sea. The results also suggest that septic tanks, such as those used at the state parks, may be less effective at containing pollution.
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.
Even “elevated levels” of caffeine are measured in nanograms per liter, well below a lethal dose for marine life. However, an earlier study by Rodriguez del Rey and Granek on intertidal mussels showed that caffeine at the levels measured in this current study can still have an effect despite the lower doses.
“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 Granek.
Results of the study were published in the July 2012 Marine Pollution Bulletin, “Occurrence and concentration of caffeine in Oregon coastal waters.”