Some 'eco-friendly' de-icers are as harmful as road salt, so what else is there? - The Weather Network

The concept of less damaging, “eco-friendly” de-icers is welcomed as a step in the right direction, but new data has shown that at least some of them actually tend to be worse than the road salt they were intended to replace.

A group of biologists from Queen’s University examined the effects of salt levels in freshwater habitats from de-icer runoffs, comparing them to some of the more eco-friendly labelled solutions such as beet juice, according to a news release. Only minimal effects on the communities were uncovered, including bacterial and zooplankton at high road salt concentrations, but researchers discovered more significant alterations with the more modern concoctions.

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More details on the impacts are included in a recent study published in the journal, Water.

The main reason the alternative de-icers such as sugar beet juice aren't as advertised is because of the sodium chloride they contain, according to Shelley Arnott, a professor and researcher at Queen's University.

"These de-icers are really just road salt with some additives. I think the problem is that some of those additives can actually be more harmful than the salt," said Arnott, in a recent interview with The Weather Network.

Two de-icers examined by researchers

The Queen's University researchers tested two types of alternative de-icers, both of which contain sodium chloride as the major component. However, one of them also has a beet juice additive and the other contains magnesium and calcium chloride, as well.

"What we found was that the product with the beet juice additive was actually way more toxic to zooplankton. Zooplankton are kind of an intermediate level of the food web, so they're really important in transferring energy from the algae, [which] are the primary producers. So, it transfers that algae up to higher trophic levels, like fish," said Arnott.

She said zooplankton are thought of as "really critical" links in the ecosystems, so if something is affecting them negatively, then it's most likely impacting the entire food web chain.

Meanwhile, Arnott noted that the beet juice brine still caused a negative impact on the zooplankton with a much smaller amount of it when compared to the road salt with sodium chloride, and the alternative de-icer with the sodium, magnesium and calcium chloride.

"Being affected at lower concentrations (referring to chloride concentrations) means that it doesn’t take as much to cause mortality or reduce reproduction," said Arnott.

To conduct the tests, researchers isolated the deoxyribonucleic acid (DNA) from the "little ponds that we made," allowing them to see all of the bacteria living in the water, according to Virginia Walker, Arnott's colleague and fellow Queen's University professor.

"What we found was that the bacteria that need oxygen to survive were gone, and those bacteria that cause bad smells and everything that don't need oxygen to survive, they're the ones that were left," said Walker, in a recent interview with The Weather Network.

Problems with beet juice as a de-icer

One reason why road salt alternatives with beet juice additives are used is they tend to stick to the road a "bit better" and you don't have to apply it as often, Arnott said.

The juice from sugar beets lowers the melting point of ice and snow, helping to clear your driveway. It’s also used to melt ice and snow on municipal roads in some areas.

"The idea is that you would reduce the amount of salt that you're putting into the environment," said Arnott.

The problem, however, lies in its toxicity, which is worse than road salt, Arnott added.

"Beets have a high amount of potassium, and potassium chloride is really toxic to aquatic organisms," said Arnott.

"There are all these sugars associated with the beet juice. Those sugars fuel bacteria, and then we see this huge drop in oxygen. Of course, oxygen is essential for aquatic organisms, and if you don't have enough oxygen, it's going to change the food web."

Walker noted that of the two de-icers, the variation with the magnesium and calcium chloride had less of an impact than the other in their studies.

"That would be one that might be explored, the magnesium chloride and calcium chloride. But that still doesn't get away from the fact that you're adding salts to the environment."

New Brunswick wetland may hold key to limiting effects of road salt runoff

So, if the idea of environmentally friendly de-icers is just a fairy tale, then what is the answer to dealing with the run-off of road salt every year? Well, New Brunswick may have stumbled upon the answer.

Earlier this year, results were released that showed a wetland connected to the City of Moncton's snow-disposal facility improved water quality. According to Ducks Unlimited Canada, chloride levels were reduced by 66 per cent to 93 per cent when comparing water samples from the inlet and outlet of the wetland.

"If we develop too close to these watercourses or [we] manipulate the system, then you start to get a decline in the ability for the the natural world to help clean these things up," said Adam Campbell, Ducks Unlimited Canada's manager of provincial operations for the Atlantic region, in a recent interview with The Weather Network.

A driving factor in the water quality improvement has been the dense vegetation in the channel leading to and within the pond, Campbell noted.

"It's quite shallow, which allows us to have a lot of emergent vegetation growing up through the surface of the water," said Campbell. "The more vegetation that comes into contact with the water, the more opportunity for absorption of nutrients. You can knock out sediment from suspension."

City of Moncton staff have been monitoring the water quality within the snowmelt collected by the wetland since 2014.

According to Ducks Unlimited Canada, run-off from municipal “snow dumps” can be particularly troublesome, and can contain gravel, salt and hydrocarbons from oil and gas, among other things.

The road salt in the snowmelt gets initially diluted by the water in the wetland, and then is absorbed by some of the plant species growing within it, acting as another source of pollutant removal, Campbell explained.

“The natural assets that wetlands provide are really impressive. The reality is we need to make sure that we maintain what we have because they're doing all of these services for us," said Campbell.

Even small doses of road salt affect aquatic species and landscapes

While the environmental effects of road salt have been widely documented, Arnott noted that aquatic organisms are affected even at levels "we thought [were] permissible."

"Any road salt is going to be bad. We know that it is toxic in aquatic environments. We have guidelines that allow for a little bit of it to go into the environment under the assumption that it's not going to have an impact on aquatic organisms," said Arnott.

The other concern with road salt is an increase in usage, another unintended consequence of climate change, Walker explained.

"As climate change occurs, we'll be pushing the window of where we can use salt farther and farther north. As far as I'm concerned, I haven't seen an eco-friendly de-icer that I would want to use, yet," said Walker.

As for the Moncton wetland project, Campbell said it should sustain itself for "quite a long time."

"We'll continue to monitor that and make sure that it's functioning the way it should," he said.

Meanwhile, Campbell wants to look for new opportunities and similar environmental projects to handle the snow, either in Moncton or adjacent to the city. Ducks Unlimited Canada has had a few municipalities reach out to it.

"I'm looking forward to seeing how that might lead to some more pond development on the landscape," said Campbell.

"We're just kind of scratching the surface here. There is likely some salt-tolerant vegetation along roadsides that can help out, and a combination of that and some wetlands might be a pretty cool path forward."