A recent study by researchers at Portland State University and Washington State University revealed the occurrence of elevated levels of caffeine in several marine locations off the coast of Oregon and traced the cause to heavy rainfall resulting in sewer overflows (and not necessarily to the proximity of local Starbucks cafes). The study (Rodriguez del Rey, Z., Granek, E., and Sylvester, S. 2012. Occurrence and concentration of caffeine in Oregon coastal waters. Marine Pollution Bulletin, 64 (7): 1417-1424) points out that while the caffeine concentrations were relatively low, the effect on marine life needs further research: “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,” said Portland State University professor Elise Granek (source).
“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. ‘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.’
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” (Ibid.).
Abstract: Caffeine, a biologically active drug, is recognized as a contaminant of freshwater and marine systems. We quantified caffeine concentrations in Oregon’s coastal ocean to determine whether levels correlated with proximity to caffeine pollution sources. Caffeine was analyzed at 14 coastal locations, stratified between populated areas with sources of caffeine pollution and sparsely populated areas with no major caffeine pollution sources. Caffeine concentrations were measured in major water bodies discharging near sampling locations. Caffeine in seawater ranged from below the reporting limit (8.5 ng/L) to 44.7 ng/L. Caffeine occurrence and concentrations in seawater did not correspond with pollution threats from population density and point and non-point sources, but did correspond with storm event occurrence. Caffeine concentrations in rivers and estuaries draining to the coast ranged from below the reporting limit to 152.2 ng/L. This study establishes the occurrence of caffeine in Oregon’s coastal waters, yet relative importance of sources, seasonal variability, and processes affecting caffeine transport into the coastal ocean require further research (Rodriguez del Rey, et al., op. cit.).
Editor’s note: These findings give “drinking like a fish” a whole new meaning…
