Vehicle tires contain a chemical called 6PPD to prevent tires from breaking down due to reactions when exposed to air. When 6PPD reacts with ozone in the air, it forms 6PPD-quinone. Tires wear down through contact with roads, releasing particles into the environment. When it rains, stormwater from hard surfaces like parking lots and streets washes these particles into streams and other water bodies. As a result, 6PPD-quinone may be present and aquatic organisms can be exposed to it. Coho salmon (Oncorhynchus kisutch) mortality has been linked to 6PPD-quinone exposure in stormwater and runoff into affected waterways.
You can find the updated BC Approved Water Quality Guidelines here.
