What's in the groundwater beneath Whitehorse? Research suggests some high levels of uranium

High levels of heavy metals and metalloids in untreated groundwater have been detected in and around Whitehorse, new research suggests.

Of main concern are arsenic, uranium and manganese, some levels of which preliminary data suggest are above safe drinking water guidelines recommended by the federal government. 

Those results still need to be confirmed through further testing. The water tested is outside of the municipal water system. 

In collaboration between Yukon University, Carleton University, the Yukon government and others, researchers analyzed samples from 182 sites across the city, including residential drinking water wells, environmental monitoring wells and springs. The researchers also used data from previous environmental monitoring studies, and tested surface water on shuttered mines in the copper belt.

The research states that 30 per cent of samples contain uranium above federal limits. One site registered levels 20 times higher than acceptable concentrations set by Health Canada. Gross Alpha — that is, either uranium, radon or radium that emit radioactivity as they decay — exceeded guidelines by 33 per cent. For arsenic and manganese, it's seven and 29 per cent above, respectively. 

The research states excess exposure to these can come with serious health risks, including kidney damage, cancer and impaired brain function.

Mary Samolczyk, an assistant professor of earth sciences at Yukon University, said behind the research is public health.

"I'm passionate about this because it's very important for people to understand what they're drinking," she said.

Groundwater is what most people in Whitehorse drink. Buildings connected to the water main have their water treated with sodium hypochlorite, which targets pathogens, at the Riverdale aquifer. The water is monitored at the pumphouse in the neighbourhood and weekly at several stations along 187 kilometres of pipes throughout the city.

Right now, the city can only treat pure groundwater. There's a possibility surface water could be mixing with groundwater, which could be prompting changes, including to the levels of metals and ions. The city recently faced $39 million pricetag to upgrade the water treatment system, but that's been delayed. Still, staff have said the city's potable water remains safe to drink.

Samolczyk said what's being found in the groundwater is naturally occurring, owing to the fact the city's built upon a lot of mineralization. The issue isn't unique to Whitehorse, she added.

"It's everywhere. We need to check the quality of our groundwater, to make sure that people are drinking what — a quality that Health Canada recommends as safe."

Researchers waiting on final results 

Joel Cubley, an associate professor with Yukon University, said the data suggests bedrock and overburden that could be naturally depositing uranium and other things into the groundwater, which he noted can be treated.

Asked whether historical mining — like what used to happen in the city's copper belt region — could be having an effect on levels so far gauged, Cubley said that connection just can't be made yet, though it's still a research focus.

Cubley acknowledged there's city-wide concern about the issue, like how to protect groundwater from industry.

"There's pressure for us as a research team to get data out into the public sphere, so it can inform decision making, and we are very cognizant of that," he said.

Researchers are waiting on final laboratory results of samples collected over the summer. Once analyzed, they will follow up with residents whose wells were tested, said Cubley, adding a final paper on the topic is expected within the next three years.

Earlier this year, the city was considering amending its bylaws that would, in effect, ban mining and exploration within its limits. One of the reasons for that: preserving groundwater. The city has shelved the topic. In a report from April, city staff stated they need more time to consult people.

Cause for concern?

CBC News shared the research with Miriam Diamond, an environmental chemist and professor at the University of Toronto. She said the levels in the research, however preliminary, should be taken seriously.

"If somebody is drawing drinking water from that location," she said, "then some of these results are of concern."

Diamond said all sample sites with high concentrations of whatever metal should be soon resampled because, over time, there can be a lot of variability. 

"Where are the locations that have high exceedances? Resample those, to make sure there's consistency, that these levels of uranium and manganese are consistently high."

While it's not yet clear whether mining has impacted levels, Diamond said it's a well known fact that the industry increases the mobility of metals.

"Mining by its very definition liberates minerals, right? It's extracting minerals from the ground. It's opening up the rock that was hitherto closed to water flow to air."