Lab microbiologist Otilia Plesiu put the small bottle of water under an ultraviolet light, as two other Portland Water Bureau employees hovered around, waiting for the verdict.
The bottle glowed baby blue.
That fluorescence on May 23 marked the third time in as many days that a sample of Portland's water had tested positive for E. coli. It triggered a boil-water notice that shut down businesses and disrupted the lives of 670,000 people.
Portland has only had three boil water alerts in its history.
Today's heavily regulated water system involves precise protocols set by the Environmental Protection Agency, with regular monitoring, detailed record keeping and a certified lab that uses checks and balances to try to prevent false results.
The process, which started with a sample drawn May 20 from a tap downhill from Mount Tabor's Reservoir 1, worked as intended last month, said Kari Salis, water quality manager for the Oregon Health Authority.
"We feel confident in Portland's results," Salis said.
Logan Bourdon, a Water Bureau environmental technician, recently demonstrated the process for an observer, offering a public glimpse at the regimen that led to the alert.
First step, he unlocked the green metal box encasing the tap.
"All of our sampling stations are protected in some way," Bourdon said.
Before collecting a sample, Bourdon fired up a torch and heated the tap to kill bacteria. Then he turned on the faucet, letting water flush out the pipe. He checked the water's temperature, acidity and chlorine level, jotting down all three.
Next, Bourdon rubbed sanitizer on his hands to avoid contaminating the sample. He capped the tap with a plastic hood, keeping the elements at bay. To draw a sample, he filled a small plastic bottle, checking to make sure he had between 100 and 110 milliliters. After completing the paperwork, he continued on his rounds.
The sampling took about 15 minutes.
In the afternoon, Bourdon dropped the sample off at the bureau's North Portland lab to test for total coliforms, bacteria that signal possible fecal contamination, and E. coli, a group of coliform bacteria that live in the intestinal tract of people and animals. When E. coli are present, so is fecal matter.
The testing, like the sampling, is regimented.
Lab employees check the bottles to ensure they are cold when they arrive. Samples are kept iced during travel to prevent the growth of bacteria, which multiply in warm temperatures.
"You don't want to be incubating it on its way here," said Yone Akagi, Portland's water quality compliance manager. "You want it to get here, and then you have a set amount of time that you incubate it."
The bottles are processed in a batch with 20 to 30 other samples plus three controls – a bottle with E. coli as a positive control, one with non-coliform organisms as a negative control and a sterile bottle of water.
Batches are nested in a bath of water and put in a refrigerator-size incubator set at 35 degrees Celsius, or 95 degrees Fahrenheit. Each batch sits 18 to 22 hours in the incubator, long enough to let organisms multiply.
The next day is showtime.
On the morning of Friday, May 23, microbiologist Otilia Plesiu removed a batch from the incubator as she always does, except this time the lab manager and another bureau specialist were watching, said Renee Chauvin, the lab's quality assurance coordinator.
When Plesiu spotted the yellow sample from Reservoir 5, she held it next to a pale yellow bottle, which serves at a comparative sample. Sure enough, the first one was darker, giving Portland its third positive coliform test in three days after Reservoir 1 and a sampling station at Southeast Salmon and Second. Plesiu put the yellow bottle under the ultraviolet light. It flouresced with E. coli.
No one gasped or fretted, Chauvin said, as they went through the prescribed procedure. Plesiu called the supervisor in charge of sampling, recorded the results in an electronic database and sent a notice to a group of Water Bureau staff, kicking into gear the process of informing the state and determining resampling sites.
Under Environmental Protection Agency rules, a positive coliform test must be followed within 24 hours with a resample at the same site and taps five links upstream and downstream.
In the subsequent tests, all of those resamples were clean, but the state ordered a boil water alert anyway. Salis, water quality manager for the Oregon Health Authority, said officials didn't want to take any chances despite the inconvenience and cost to businesses.
"It's not that common to get E. colis," Salis said. "That means there is fecal matter in the water. It's a public health risk."
-- Lynne Terry