Although Chavez found E. coli levels at Blue Lakes to be well within Environmental Protection Agency guidelines, he expressed concern about the fact that local waterways are not monitored for harmful bacteria on a regular basis.
He said, “E. coli is naturally occurring. It comes from the fecal matter of warm blooded animals, so in an open environment like Blue Lakes where humans and wildlife have access to the water, I knew I’d find some E. coli. Since I like to swim and kayak and fish there, I wanted to know if it was safe.”
At each step of his project, Chavez strictly adhered to well established scientific protocols to avoid contaminating his samples and to assure they remained stable until he could perform lab tests and analyze the results.
“I worked with Zee Hopper, the head scientist at Alpha Labs. She and her manager were really generous with me, allowing me to use the lab for my experiments,” Chavez said.
Chavez collected three samples at eight GPS coordinates at Blue Lakes (24 total samples), choosing both highly populated areas near resorts as well as more remote areas. Because of the expense of laboratory testing, he processed samples from five of the eight testing locations (15 total samples).
He enlisted the help of his mother and grandmother, who recorded data and drove the electric boat for him. Chavez used sterilized canning jars to collect water, dipping the jars six inches into the water with a gloved hand. He said, “Six inches is about where most people’s mouths would be while they’re swimming.”
He immediately put the samples in an ice-filled, insulated cooler, then took them to the lab for testing.
Federal guidelines for E. coli suggest that 200 mpn or less of E. coli per 100 ml of water is safe for recreation. According to the World Health Organization, the microbiology measure of most probable number (mpn) is a standard measure for coliform bacteria, including E. coli. In this method measured portions of a water sample are placed in test-tubes containing a culture medium. The tubes are then incubated for a standard time at a standard temperature.
“I used a colilert reagent that turns yellow and glows under ultraviolet light,” Chavez said. Colilert reagent is used for the simultaneous detection and confirmation of total coliforms and E. coli in water. Colilert utilizes nutrient indicators that produce color and/or fluorescence when metabolized by total coliforms and E. coli.
The area with the highest E. coli concentration, between 25-35 mpn/100ml, was at the northwest end of Blue Lakes near La Trianon Resort. The area with the lowest concentration, between 4-8.5 mpn/100ml, was near the Narrows Resort closer to the north/south midpoint of Blue Lakes. The vast majority of testing sites showed less than 15 mpn/100ml.
Because he spends so much time at Blue Lakes and other recreational waterways in Lake and Mendocino Counties, he would like to see water quality signs posted that reflect monthly testing.
“They could use a stoplight indicator: green for ‘It’s safe;’ yellow for ‘It’s okay to walk along the shore;’ and red when the bacteria levels exceed EPA safety standards,” he said. When asked whether he would continue to swim and fish in Blue Lakes, he said, “Yes, I love it!”