Even the Sound is getting a caffeine buzz

The region's love affair with coffee is spilling into Puget Sound in such large quantities that scientists have had to scrap plans to use caffeine as a marker to pinpoint cracked sewer pipes and other sources of human-waste pollution.

Scientists had seen caffeine as a promising "tracer," since it does not occur naturally in the environment, is ingested only by humans and remains virtually unchanged as it passes through the body. But the substance is everywhere in the Sound, because motorists and espresso-cart operators dump cold coffee into storm drains.

"We had eight monitoring stations set up in Puget Sound," King County water-quality planner Scott Mickelson said, describing a year of tests. "And we were very surprised to find caffeine everywhere, from Admiralty Inlet to Vashon Island."

Specifically, caffeine was found in more than 160 of 216 samples and at depths of up to 640 feet.

Further study of the Sound and Lake Washington has been abandoned as a result. Mickelson said the county will revert to using dye tests to track waste.

In Lake Washington, where the county also had hoped to use caffeine tracing, DNA tests will continue to be used when E. coli and fecal coliform are detected, to determine whether such contamination originates from humans or animals, county limnologist Jonathan Frodge said.

A 1996 county study indicated caffeine in area waters rises dramatically after people have their first cup in the morning. In that study, one of the automatic samplers set in the Duwamish River measured sewage overflow between 4 and 8 a.m., the other between 4 and 8:30 a.m. Despite the small difference, the second sampler showed total caffeine levels eight times higher than the first.

Mickelson said little is known about the effects of caffeine on wildlife but the caffeine in Puget Sound is so diluted it probably has a minimal effect.

He said the Sound appeared to be clean overall, with tests coming back negative for traditional toxicants such as pesticides, herbicides and semi-volatile chemicals. Only background levels of heavy metals were found, though high levels of heavy metals found in sediment in the Duwamish River may lead to it being federally classified as a polluted site.