The road salt that makes winter driving safer may be killing salmon

This winter has seen more snowfall in the Lower Mainland than just about any other in recent memory.

And with that snowfall comes the regular side-effects—heated debates over shovelling sidewalks vs bike lanes; bent fenders; slips; falls; gleeful children tobogganing.

But one important side-effect of the snow that often goes unnoticed—at least to the average person—is the salt that is spread by governments and property owners to lower the melting point of snow on roads and sidewalks.

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Good for driving, bad for fish

While the practice improves road safety, it has negative effects on the local ecology. After the snow melts away, the salt may be absorbed into the ground or washed into storm sewers.

Atop Burnaby Mountain, that groundwater is the source for streams like Stoney Creek, while many storm sewers also flow into local streams.

And that may hold back decades of conservation work that has been done on streams like Stoney Creek.

A local salt monitoring program is aiming to change that and to achieve stricter regulations on the application of road salt to deal with snow.

In fact, Alan James, a member of the Stoney Creek Environment Committee, would like to see it eventually phased out altogether.

James, a retired geophysicist and computer scientist, is a volunteer with the committee and has been keeping an eye on the road salt issue since 2008.

For the majority of that time, the work has included attending monitoring equipment in Stoney Creek to download data. But in the last year or so, he’s gotten his hands on something a bit more modern.

In an application on his phone, James can view real-time data from the streams, thanks to new, automated loggers that regularly upload data via cellular signals to the app. At any given moment, James can open his phone and see how much chloride is in the creek.

Correlation or causation?

In an interview about a year ago, James said he believed there was a correlation between road salt and chloride contamination of local streams, but he wasn’t particularly comfortable saying there was a causal relationship.

But over the past year, he has become more and more convinced.

“I’m more comfortable saying it’s causal, but it’s still not proven. The only way to do that would be to have somebody actually [record] the time that the truck went by the creek and then compare it to the time that they came,” James said in an interview this week.

Still, the correlation between the two is notable. On the SCEC website, graphs of data from three loggers—one in Stoney Creek, one at Cariboo Dam, and one in Eagle Creek—show spikes in chloride levels coinciding with temperatures dropping below 0C, when road salt may have been applied.

And the spikes are far from subtle. In many cases, they resemble spears jutting upwards, out of otherwise relatively stable lines.

In Stoney Creek’s Tributary 3A, the chloride levels hold steady under 100mg/L for weeks in November and early December before shooting suddenly to nearly 1,000mg/L around Dec 6, the first recorded contamination of the season.

The chloride levels then drop off nearly as suddenly as they rose, returning to the ambient chloride levels.

Eagle Creek similarly saw levels rise from the 100-250mg/L range to close to 1,000mg/L in time with temperatures dipping below freezing.

Road salt is toxic

At around the same time as the automated loggers were brought in, James contacted Chris Wood, an adjunct professor of zoology at UBC, along with a number of other UBC faculty members.

Wood specifically studies toxicology and its effects on aquatic animals, like fish, and James sought his expert advice on a salt monitoring program.

Scientific research on chloride-contaminated streams has “really exploded in the last five years,” Wood said, particularly with research from the US and Europe, as well as some studies in Eastern Canada.

“Pacific salmon are under incredible pressures, and this is just one more very serious load on them in urbanized areas.”

Photo: Dustin Godfrey / Burnaby Beacon

“We call it, now, the salinization syndrome, which is associated with excessive application of salt,” Wood said. “What I’m reading is that the effects are really devastating.”

In fact, the federal government declared road salt to be a toxic substance as far back as 1999.

BC government guidelines put the upper limit for prolonged exposure to chloride at 150mg/L, while the short-term exposure shouldn’t exceed 600mg/L. That’s well below the near-1,000mg/L levels being reached in Burnaby.

And the effects of road salt and chloride contamination can be serious. One 2018 study noted Atlantic salmon alevins—that is, freshly hatched salmon—saw “significantly higher” mortality rates when tested with concentrations of 100-1,000mg/L.

James said salt-contaminated creeks have also been shown to cause abnormalities in development and even hemorrhaging in alevins’ yolk sacs just after hatching.

And there may even be an effect on benthic invertebrates, the small animals young salmon feed on before they head to the ocean.

Struggling streams

Part of the importance of the issue is that salmon returns have been diminishing for decades, although streamkeeper organizations like SCEC have managed to boost some local populations over the years.

“Pacific salmon are under incredible pressures, and this is just one more very serious load on them in urbanized areas,” Wood said.

And Stoney Creek, despite the efforts of streamkeepers, has seen its share of challenges, from sewage contamination to an unknown contaminant that killed hundreds of fish in the fall.

After some conversation about the monitoring project, James and Wood got to wondering whether the problem would be more widespread than just in Stoney Creek.

“We decided, in fact, that it was worth trying to raise funding for a more ambitious project, not just for Stoney Creek, but for many other local salmon spawning streams,” Wood said.

James reached out to streamkeeper organizations throughout the Lower Mainland to gauge interest in participating in the program—Wood said the hope is to get monitors into 30 different streams.

So far, Wood said about 15 local streamkeeper organizations throughout the region have signed onto the project if it goes ahead.

James said that includes organizations in Surrey and even as far out as Chilliwack.

Getting universities involved

In order to fund the five-year project, the group is seeking close to $600,000 from the Natural Sciences and Engineering Research Council, a funding arm of the federal government.

Much of that money would be going toward training students, with three post-secondary schools—UBC, BCIT, and SFU—signed on to the project, including research projects from PhD students and masters students.

“Each of the students would have their individual projects, which would either be the project or the thesis which would help them earn their degree,” Wood said.

Among the projects being looked at are a proposed UBC PhD thesis looking at the effects of salt on the physiology of coho and chum salmon. That would particularly focus on early-life development and would span four-and-a-half years for that student.

“I’m hoping that a scientific study will be sufficient to get them to make salt regulated in the same way that they regulate pesticides like roundup.”

Photo: Dustin Godfrey / Burnaby Beacon

A pair of masters students are looking to do offshoot projects that would focus on specific aspects of the amount of salt in the water and fish development.

SFU students are expecting to look at the effects of road salt on the young salmons’ food source, the insect larvae and benthic invertebrates.

BCIT students, meanwhile, will be doing shorter projects over three or four months that would get into some of the more granular details.

If the project doesn’t get the funding they’re seeking from the research council, Wood said all hope is not lost. The Pacific Sciences Enterprise Centre—part of the federal Department of Fisheries and Oceans—has been “very generous with the time of one of their employees,” he said.

And if the funding from the research council falls through, Wood said the group will seek funding straight from the source.

The positive impact of citizen science

On the West Coast, the issue often goes under the radar because the Lower Mainland only sees snow a couple of times per year—usually.

But since he started on it in 2008, James said he’s happy to have seen his SCEC work on road salts incur changes at SFU. But in the past 14 years, the federal government has still failed to adequately regulate the use of road salt, he said.

Wood said the work being done by citizen scientists like James has had a major effect on environmental issues.

“I think in general, governments, regulatory bodies are becoming much more receptive to what I would call bottom-up science and bottom-up concern about environmental issues,” Wood said.

“I think that the sort of activism Alan in particular, and many of his colleagues, [has] shown is great. I wouldn’t be involved in it myself, unless he reached out to me and asked for a little bit more scientific expertise.”

‘Use less salt’

Research has generally shown road salt to be detrimental to local streams, and governments even acknowledge that. But so far, James said, they haven’t taken adequate action.

Action on reducing or eliminating salt could also help beyond the streams—salt also has a damaging effect on the roads it’s spread on and on the cars that drive over it.

And there are alternatives to salt. Calgary, for instance, has had a successful run using beet juice combined with a brine.

But at the very least, James and Wood said, there needs to be work done to reduce the amount of salt that is used. They said people frequently use far more than is necessary.

“I’m hoping that a scientific study will be sufficient to get them to make salt regulated in the same way that they regulate pesticides like roundup. The operators need to have training and certification, and right now it’s a free-for-all,” James said.

“There are lots of techniques that can be used, and most of them are: use less salt.”

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