A study conducted by two University of British Columbia researchers indicates that high levels of salt used on winter roads may be killing fertilized coho and chum salmon eggs in freshwater streams in the Vancouver area.
A report on the study, which was launched three winters ago by zoology masters’ students Carley Winter and Clare Kilgour and released Jan. 2, has raised concerns about use of road salt.
The report recommends that municipalities switch to brine for melting ice on roads, as it not only uses up to 50% less salt but is more effective at sticking to streets and sidewalks. Such action would save salmon, but also taxpayers’ money, the researchers found.
The study, which is preliminary and yet to be peer-reviewed, found that the largest pulses of salt were 10 times higher than British Columbia’s acute water quality guideline for chloride in freshwater systems, equivalent to almost 30% of sea water.
The data suggests that salting roads at current levels in November or December, when many salmon species are spawning and embryos are developing in streams, could be dangerous to both coho and chum salmon.
Researchers suggested that residents salting their driveways spread salt out rather than placing it in clumps, which achieves the same effect with much less salt.