Instead, they found elevated levels of the familiar, morning-enhancing chemical near Carl Washburne State Park and Cape Lookout, two areas not near potential sources. Relatively high levels of caffeine also showed up in many samples taken from the northern coast following a heavy, late-spring storm.

 

This pattern suggests that while wastewater treatment plants appear to be effective at removing caffeine, heavy rainfall can wash it, along with sewage overflow, out into the ocean, the researchers write in the July issue of the journal Marine Pollution Bulletin.

 

Septic tanks like those used at state parks may be less effective at containing contaminants, researcher Elise Granek, assistant professor of Environmental Science and Management at Portland State University, said in a statement.

In spring 2010, graduate student Zoe Rodriguez del Rey and Granek sampled water from 14 coastal sites and seven other water bodies as far north as Astoria, Ore., and as far south as Brookings.