When winter arrives, it’s common to see heaps of road salt used to melt the snow and ice. Now the work of a group of citizen scientists has demonstrated that the practice of salting snow-covered pavement could be killing newly hatched salmon in the streams near you.
The dissolved salt makes its way through the soil into groundwater, streams and creeks. A group of citizen scientists in Burnaby has spent the past two decades studying the impact of salt contamination in Stoney Creek on the survival of the keystone species.
Over the years, Stoney Creek has been inundated with salt deposits washed down from the open salt shed on the SFU campus on the slope of the Burnaby Mountain. The salt contamination in the groundwater around the creek has also added to its contamination level over time. The citizen scientists and members of the Stoney Creek Environmental Committee (SCEC) convinced SFU to take action and record the conductivity of electrical flow in the creek water, which helps gauge the level of salt or chloride contamination.
The group monitored the hatching of 600 chum salmon eggs in a salt contaminated stream as well as in a clear tributary and found a direct link between the high salt contamination and mortality of salmon alevin – newly hatched eggs.
“Salmon eggs are incredibly resilient. But the moment they hatch, they are no longer protected by the solid membrane. Many alevins released in the salt contaminated section of the creek showed haemorrhaged yolk sacs, which reduces their chances of survival,” said Alan James, one of the citizen scientists associated with the SCEC.
In response to this study, the Simon Fraser University enclosed the open salt shed and began using innovations in road management techniques to avoid the use of road salt.
“They have reduced their use of road salt by half since 2005 and are being more careful about how they use it. They use a brine first. This helps the granular salt stick to the road and not dissolve into the soil. They also use beet juice, which is an interesting alternative,” James said.
“In cities with heavy snowfall that gets frozen, using gravel and sand is an alternative to road salt. But for others, we need to get creative,” he added. The Stoney Creek monitoring project is still underway and data loggers have been consistently sampling the water and uploading the data.
However, with the help of other streamkeeper groups, a team of zoologists from UBC and coordination from the Pacific Science Enterprise Centre in North Vancouver and Fisheries and Oceans Canada, the SCEC is widening the project to include other streams in the lower mainland.
“Road salting is a Canada-wide problem. If we collect more data across multiple streams and creeks, and reveal the grim reality of the survival of the salmon alevins in salt contaminated waters, maybe something can be done about it. We need to find large scale alternatives,” James said.
For more on the work of the Stoney Creek Environment Committee visit them here.