The parasite found in Baltimore-area drinking water last week can be identified by lab testing in as little as 24 hours, scientists and laboratory managers told The Baltimore Banner. But Baltimore City’s Department of Public Works said it would be another week before it gets new test results, leaving the public in the dark about the state of the water supply in the meantime.

DPW announced Thursday that low levels of cryptosporidium had been detected in Druid Lake Reservoir, an open-air reservoir that feeds into the water supply for parts of Baltimore City and Baltimore County, as well as Howard County. The city is working to install storage tanks to protect the reservoir’s drinking water by the end of the year, as required by a federal consent decree. It’s also required to conduct monthly tests, which was how the parasite was detected in a water sample taken Sept. 19. The results were reported from an outside lab a week later, on Sept. 26.

DPW took another sample the next day, last Wednesday, but said they were at the mercy of the lab’s processing time, which would delay results by another week.

One week is standard turnaround time for routine testing of crypto, as the parasite is called for short, said Susan Boutros, founder and president of Environmental Associates, a microbiology laboratory in Ithaca, New York, that was certified to perform testing for cryptosporidium and other microorganisms for over three decades. Testing is complicated and cumbersome, she said, and requires its own certification. It must be performed according to detailed protocol set forth by the Environmental Protection Agency, which requires considerable technical expertise.

But in the wake of confirmed — or even suspected — crypto contamination, it is common for certified labs to perform 24-hour testing for an additional fee, Boutros said. DPW uses Analytical Services Inc. in Williston, Vermont, to perform its crypto testing; the lab did not respond to The Banner’s inquiry on whether it provides 24-hour testing or how much that costs.

Jennifer Combs, public relations coordinator for DPW, said the agency’s decision not to pursue a faster turnaround for follow-up test results was “not a cost issue.” Rather, she said, a week was the quickest timeframe that Analytical Services was able to offer.

The city’s apparent lack of urgency is concerning, said Boutros, whose company was one of the nation’s first commercial labs equipped to test for giardia and cryptosporidium in the 1980s. A single sample is a “snapshot in time,” that yields a “momentary glimpse of what’s happening in that water supply.”

But, “if you found it here today, you don’t know what it was yesterday, what it’s gonna be six hours from now,” she said, which is why follow-up testing, with multiple samples and quick turnaround time, is critical to assess levels of any contaminant once its presence has been confirmed and to guide decisions on the response.

Combs said the city drew a single sample for both the initial routine test and the follow-up test done eight days later.

Cryptosporidium infection can cause diarrhea and other gastrointestinal issues for people who are immunocompromised, who were advised to boil water before drinking it. Elderly people and children may also be harmed by the parasite, though healthy people are not considered high risk for infection at current low levels of contamination, city officials said during a press call on Thursday.

Boutros said the low level of crypto reported by DPW officials — 0.09 oocysts per liter — becomes more of a problem in the absence of timely follow-up, “because we really don’t know what’s going on.” Still, “if you see one good crypto, you have a problem,” she said, because it takes very little exposure to become infected

Since testing for crypto is only required by the EPA when a local water supply is high-risk — with uncovered reservoirs, such as Baltimore’s, or frequent problems with failure of water infrastructure or contaminants in the water supply — the testing is “low demand,” Boutros said. There are only a handful of certified public labs nationwide, so most states outsource the specialized, expensive testing to private labs frequently located out of state.

Dirk Whipprecht, technical manager at LabCor, a certified crypto lab in Seattle, Washington, said it provides 24-hour testing for public and private clients at a price of $692, compared to $450 to issue results in a week.

Laboratory giant Eurofins, which has various locations on Maryland’s list of state-certified water quality labs, also does 24-hour testing, according to Jennifer Laws, account executive for built environment testing, for a fee similar to what others in the industry charge. Eurofins serves both public utility and private industry customers, Laws said, and they field “a few inquiries per month” from clients needing expedited testing.

When dealing with a drinking water contamination event, the timely turnaround of follow-up testing “is important to understand if the threat is expanding or if it was an isolated event,” said Natalie Exum, assistant scientist in the Department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health. People and institutions “must change their day-to-day decisions to protect themselves from contaminated drinking water, and it is in everyone’s interest to make the testing as frequent as possible with the results communicated to the public as quickly as possible,” Exum said.

Baltimore officials noted last week — and DPW said again in its emailed response Monday to questions from The Banner — that there are no regulations for notification and testing post-contamination.

The Maryland Department of the Environment and Maryland Department of Health said in a statement that they would “continue to work closely with the Baltimore City Department of Public Works and our federal partners at the EPA to ensure that city drinking water customers are informed on this matter and appropriate steps are taken to minimize risks to public health. This includes the importance of Baltimore City completing its capital project and discontinuing its use of uncovered reservoirs for treated drinking water.”

Baltimore can learn from the responses of other localities to hundreds of crypto contamination events that have taken place nationwide, Boutros said, and reach out to officials from other cities who’ve had this experience.

She recalled a suspected crypto outbreak in Washington, D.C., in 1993, for which her lab at the University of Pittsburgh in Bradford, Pennsylvania — where she was a professor of life sciences for 24 years — conducted two back-to-back cycles of 24-hour testing on multiple samples for the district. A boil-water order had been issued for all residents after a problem at the treatment plant was identified and high levels of turbidity — or cloudiness — indicated an elevated risk of contamination.

Officials required two consecutive negative crypto tests before lifting the boil water order. Crypto was never detected during that incident, Boutros said.

In addition to rapid testing, officials used other epidemiological methods to determine if there had been an outbreak, she said, including phone surveys of residents to see if they’d experienced recent gastrointestinal illness, and contacting hospital emergency departments and pharmacies to see if they’d seen an uptick in GI complaints or if over-the-counter medications to treat these ailments were flying off the shelves.

“We’ve seen this before,” Boutros said. “We’re not reinventing the wheel here.”

Combs said DPW does have an emergency response plan “to deal with water contamination” but did not provide further details on its contents.

This story has been updated with comments from the Baltimore City Department of Public Works.

sarah.true@thebaltimorbanner.com

This story has been updated to note that Druid Hill Reservoir is one of several open-air reservoirs managed by the Baltimore City Department of Public Works.