Plastic, clothing fibers and CO2 are not the only things ending up the sea. So is caffeine.

Scientists at Portland State University and Washington State University, Vancouver, found caffeine concentrations off the coast of Oregon. To their surprise, the substance was not always concentrated around population centers or pollution sources. In fact, they found coffee contamination in wilder areas, likely because wastewater-treatment plants have to adhere to higher standards than septic systems. They also discovered that caffeine levels spiked after storm-caused sewer overflows.

Since the Pacific Northwest has no sources of naturally occurring caffeine, its presence in coastal waters shows that waste from human sources is leaching into the sea. The National Oceanic and Atmospheric Administration (NOAA), one of the project’s funders, said in a news release: “The presence of caffeine in ocean water may also signal additional pollution such as pesticides and pharmaceuticals.”

The presence of caffeine in the waters near Carl Washburne State Park in Florence and at Cape Lookout is another example of human habits affecting our wild neighbors.

Coffee is not the only source of caffeine. It is found in other beverages, many food products, and in some pharmaceuticals.

Marine animals are not just ingesting our coffee. They are absorbing the whole chemical soup. More research is needed before we will understand the consequences. In the meantime, the study raises concerns about inadequately treated wastewater entering our fresh and salt water resources.

Dana Kolpin of the U.S. Geological Survey has studied caffeine and other contaminants in streams near treatment plants. Speaking with National Geographic, she said, of the new findings, that aquatic organisms are getting hit with a soup of low-level contaminants.