Monitoring Tire Wear Toxins in Streams

Monitoring Tire Wear Toxins in Streams

Beaufort Watershed Stewards are part of a Vancouver Island study that is monitoring streams along the east side of the island for evidence of tire wear toxins. The study is run by the BC Conservation Foundation (BCCF) in partnership with Vancouver Island University (VIU), University of Victoria (UVic), local First Nations, and a network of community-based stewardship groups.

One key toxic compound that this study monitors is known as 6-PPDQ. It is lethal to salmon species, particularly coho, at extremely low concentrations.  The toxins enter streams when particulate from tire breakdown gets washed into streams during rain events.  When there is a significant rain event, volunteers from Victoria to Campbell River are out streamside collecting samples before, during and after the rain.  We collect samples both downstream of bridges and, when possible, directly off the bridge.  While “interesting” to access, bridge scuppers give a very informative picture of what is coming directly off bridge surfaces. 

The data that are in so far show variation in the streams, with some having high concentrations of 6-PPDQ.  Not surprisingly, the streams and rivers showing the highest toxin concentrations have high traffic density and high volumes of rain runoff directed into streams without the advantage of bio-retention strategies.  To explore the data-to-date on an interactive map, click HERE

There are many questions to answer, such as “How do toxin concentrations vary in relation to timing of rain and distance from the source?” And “How can biofiltration help remove toxins?” Answers to these questions inform possible mitigation solutions such as wetland filtration, bio-retention ponds, swales and other green infrastructure.  The University of Victoria team is building model microsystems that replicate the functions of wetlands and rain gardens. As part of their research they will test various bio-filtration media, designs, and plant species to identify efficient ways of detoxifying roadway runoff. The goal is to determine optimal strategies to help remove some or all of the 6-PPDQ in runoff before it reaches local waterways.

To learn more about the research see www.tireweartoxins.com

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