Two University of Minnesota researchers plan to study whether the coronavirus could be traveling from wastewater into drinking water supplies — and posing a potential health risk.
Timothy LaPara and Raymond Hozalski, professors in the university’s Department of Civil, Environmental and Geo-Engineering, say they believe most public drinking water supplies are safe, because water treatment plants use a process that kills pathogens such as viruses.
But they think there could be a potential risk of the virus that causes COVID-19 traveling in an infected person’s waste into a septic system, where it could leak into the groundwater. From there, they speculate that it has the potential to get into a private well, or into the public water supply in a handful of cities that do not disinfect their drinking water.
“We fear these are susceptible to contamination, and there is an opportunity for these pathogens to get people sick,” LaPara told the Legislative-Citizen Commission on Minnesota Resources during a virtual meeting on Thursday.
The commission, which oversees the spending of state lottery proceeds targeted for environmental projects, approved $59,000 for the study, using funds the Legislature approved in 2018 for emerging issues. Gov. Tim Walz must approve the request, which he is expected to do.
The Centers for Disease Control and Prevention has said the novel coronavirus has not been detected in drinking water, and conventional treatment methods of filtering and disinfecting water should get rid of it.
However, the CDC has also said that it’s unknown how much of the virus is shed in an infected person’s stool — and how high the risk of transmission might be. A recent Australian study detected the novel coronavirus in raw sewage, raising concerns it could get into the environment.
LaPara and Hozalski plan to test samples from public water supplies and private wells for the coronavirus. The public systems will include cities that get their water from a river or lake — such as Minneapolis and St. Paul, which draw theirs from the Mississippi River — and cities that pump water out of the ground.
The majority of Minnesota cities use chlorine to disinfect their water, but a few do not, LaPara said. The researchers plan to sample both types of municipal water supplies.
LaPara said they’re not expecting to find any problems with drinking water supplies in places where most residents are connected to city sewer and water treatment systems.
“We’ve got a pretty good idea when those are done right, those are very robust systems that protect public health,” he said.
Septic systems also treat sewage, but they do so by separating solids into a tank, then slowly releasing the remaining wastewater into the soil. Studies have detected other viruses in groundwater that likely could be traced back to leaking septic systems or sewer pipes or animal waste, LaPara said.
The researchers plan to start collecting samples in early May, and hope to have their work completed by the end of June. They also have requested additional funding to continue the study over the next two or three years.
COVID-19 in Minnesota
Health officials for weeks have been increasingly raising the alarm over the spread of the novel coronavirus in the United States. The disease is transmitted through respiratory droplets, coughs and sneezes, similar to the way the flu can spread.
Government and medical leaders are urging people to wash their hands frequently and well, refrain from touching their faces, cover their coughs, disinfect surfaces and avoid large crowds, all in an effort to curb the virus’ rapid spread.
The state of Minnesota has temporarily closed schools, while administrators work to determine next steps, and is requiring a temporary closure of all in-person dining at restaurants, bars and coffee shops, as well as theaters, gyms, yoga studios and other spaces in which people congregate in close proximity.