Coffee drinker are polluting the Pacific Northwest shoreline, specifically the area of the Pacific Ocean located off Oregon. A new study suggests that contaminants in human waste are entering natural water systems.

Scientists examined “potentially polluted” sites near sewage-treatment plants, large communities and river mouths along with remote waterways and state park areas.

According to Nat Geo:

“Surprisingly, caffeine levels off the potentially polluted areas were below the detectable limit, about 9 nanograms per liter. The wilder coastlines were comparatively highly caffeinated, at about 45 nanograms per liter.”

Study co-author Elise Granek writes:

“Our hypothesis from these results is that the bigger source of contamination here is probably on-site waste disposal systems like septic systems.”

Granek adds:

“Wastewater-treatment plants, for the most part, have to do regular monitoring to ensure they are within certain limits.”

While caffeine saturation has been monitored in the past that documentation has most often been freshwater and not marine in nature.

Researchers are not yet sure how caffeine concentrations affect wildlife and plant life.

Other contaminants found in ocean waters have included pharmaceuticals, hormones, personal-care products and artificial sweeteners.

While current caffeine saturation will need to be studied researchers have performed some tests. In one study researchers found that intertidal mussels produce specialized proteins in response to environmental stress.

According to one researchers: