Quantifying Road Salt Contamination in Salmon Bearing Streams within Metro Vancouver, BC

The salinization of freshwater ecosystems due to road salt application is threatening ecosystem health and biodiversity. Road salt application in Metro Vancouver typically occurs during the same time period over which juvenile Pacific salmonids are incubating and rearing in-stream. Of particular concern are the acute, episodic increases in salinity that result from salt influxes to the natural stream environment. This study quantifies road salt contamination in three urban salmon-bearing streams using real-time data loggers to monitor electrical conductivity, a proxy for salinity. Road salt contamination was recorded at each site with peak conductance measurements ranging from 183 µS/cm to 19,939 µS/cm. Acute and chronic provincial water quality guidelines for chloride were breached at each site during the winter season. Management recommendations for mitigating road salt impacts to the environment include reevaluating appropriate application rates and improving application technology, ecological restoration approaches, and providing educative opportunities to stakeholders.