News

What if La Plata County communities could detect the prevalence of COVID-19 in neighborhoods or communitywide before it shows up in test results?

Colorado entities are testing a tool to do just that, using a communal sample that is already available in underground pipes: wastewater.

Many people shed COVID-19 particles in their stool, even before they start having symptoms or if they are asymptomatic, according to the Colorado Department of Public Health and Environment. In late December, the department launched a pilot project to track those particles.

Front Range cities have already shared months of monitoring data, but the state’s new dashboard doesn’t show much from the Western Slope. In La Plata County, big questions loom for wastewater service providers and public health professionals interested in the idea.

“One of the big questions is, what do we do with this data? Is it going to give us something actionable?” said Jarrod Biggs, assistant utilities director for the city of Durango.

To track COVID-19 in wastewater, operators draw samples for laboratory analysis. If COVID-19 is present, the samples will include particles called SARS-CoV-2 RNA.

The amount of this RNA in wastewater has been tied to the prevalence of COVID-19 in a community in early research, according to the CDPHE COVID Wastewater Monitoring website.

That means monitoring wastewater could give early warnings about an upcoming surge in cases, especially when analyzed alongside other types of COVID-19 data, said Brian Devine, interim environmental health director with San Juan Basin Public Health.

Depending on where samples are taken, operators could see if COVID-19 is present systemwide, in specific neighborhoods or even dormitories, Devine said.

“It’s definitely a complementary process,” he said. “It’s not going to replace any of the other monitoring programs that we have going on, but we’re really excited to see how we can start using some of those data.”

Taking action locallyPublic health agencies could use the information to increase or decrease resources when necessary. For example, the data could inform when, where and how SJBPH does its community testing.

“I don’t think we would ever use data at the utility scale to say, ‘Actually things are getting much better, and we don’t need public health practices anymore,’” Devine said.

First, more wastewater operators would need to start sampling with greater frequency, he said.

One subdivision has already started testing for COVID-19: Edgemont Ranch, a metropolitan district of about 1,200 to 1,500 people located 7 miles northeast of Durango.

Edgemont has sampled its wastewater three times since early December. The results showed no COVID-19 particles immediately after Thanksgiving, then a peak in mid-December and a decrease in late December.

“This is helping us set our background and understand our risk,” said Robert Ludwig, a wastewater operator with the district. “It basically tells us if we’re getting worse or getting better.”

Durango considered the idea in the spring, but moved on when it seemed to be more costly than beneficial, Biggs said. City staff members are looking into the idea again.

“We’re all just exhausted with taking our temperatures every day and trying to keep our crews healthy,” he said. “If we can get another data point behind that, that’d be awesome.”

Enough bang for the buck?But wastewater monitoring is a new tool that requires more research and comes with limitations, according to CDPHE, Devine and Biggs.

For example, it only monitors large segments of the population, not individuals who may be ill. About half of people won’t shed RNA in their stool, and people might shed RNA for differing amounts of time. Movement in commuting or tourist populations might not be reflected in the monitoring data, according to CDPHE.

Moving populations and whether the data will offer enough “bang for the buck,” were the top questions for Biggs this week.

Durango’s population fluctuates by thousands of people every day because of commuting and tourism. Operators would have a hard time tracking the origin of the viral signals in the wastewater, Biggs said.

“We would want a sample at the wastewater plant and then potentially go find five or 10 manholes to sample at to get some broader picture,” he said.

Staff members could sample at different locations in the collection system, like a line with no hotels on it, but more sampling sites also increases the cost for the city, Biggs said.

He also questioned what economic relief or public health steps would be triggered by rising or falling COVID-19 signals in the wastewater.

“It’s still just data, so it has to be weighed and thought about,” Biggs said. “The bigger that data set gets, I think we can figure out how to best use it.”

For Edgemont Ranch, it costs $320 to process the samples – which Ludwig said was worth it.

“We just feel this information is valuable to us going into this wastewater plant build and understanding our risk,” Ludwig said. “(The community) can look at real COVID data for their subdivision. As long as we’re trending downward, we’re doing pretty good.”

smullane@durangoherald.com