It began as a mystery for local water experts in San Diego County: numerous area streams showing the presence of caffeine, a stimulant with no natural source in California.
A team from the state’s Surface Water Ambient Monitoring Program (SWAMP) pulled samples from 85 different locations across the county and found caffeine in 49 locations. According to a February fact sheet, from the Regional Water Quality Control Board, the group was finding similar results year round in a seven-year period from 2008-2015.
According to scientists, caffeine is not typically toxic to aquatic organisms but it is a good indicator of other potentially harmful compounds usually found in wastewater, like extremely small pieces of plastic debris, viruses, pathogens, and pharmaceuticals.
Some of the SWAMP results weren’t that surprising, Carey Nagoda, a water resource engineer for the regional water board said. Finding caffeine in developed areas near wastewater treatment plants, near septic systems, leaky sewer lines and elsewhere with large concentrations of the public is expected, she said. What did stump them, was finding caffeine where there was little human activity, which according to the Board was “contrary to expectations.”
Nagoda did a lot of field work to analyze samples. She told NBC 7 Investigates, “the main puzzle was why were we finding in remote areas we considered pristine?”
She reviewed the data and noticed a pattern. In doing so, she was able to confirm and solve the mystery of the caffeine showing up in those “pristine areas.” The discovery?
“Where there was high recreational use we found caffeine hits. When there wasn't, we didn't find them,” Nagoda said.
In other words, she found the cause of the caffeine was people enjoying the outdoors, hiking, fishing or horseback riding, relieving themselves along the trails, sometimes directly into streams and lakes she suspects.
While it’s important for people to recreate “we don’t want them to destroy the habitat," Nagoda said.
“Animals live in the stream, maybe the caffeine is okay in your body but it’s not okay for the bugs,” which live at the bottom of the stream, she said.
According to Nagoda, the bugs supply the food for fish and other life in and around the water systems that drain to major rivers and the ocean in our region.
One proposed solution is restroom facilities at popular trail locations.
The water board’s Senior Environmental Scientist Chad Loflen sent a letter of support for a United States Forest Service project for the popular Three Sisters Falls to provide, among other things, restroom facilities at the trailhead. In the letter, he noted the nearest public restroom was thirty minutes away by car.
NBC 7 Investigates is working for you. If you have more information about this or other story tips, contact us: (619) 578-0393, NBC7Investigates@nbcuni.com. To receive the latest NBC 7 Investigates stories subscribe to our newsletter.