b'Miller Creeks LegacyA t the Miller Creek field lab in Normandy Park, WSU researcher, Nathan Ivy, is observing in real-time the impacts of how rain events carry contaminants such as 6PPD-quinone into the salmon-bearing creek.6PPD is a chemical that prevents automotive tires from degrading (i.e., breaking down) and helps them last longer. When 6PPD is exposed to air, it reacts with ozone to create 6PPD-quinone (also known as 6PPDQ). 6PPDQ is lethal to coho salmon and can contaminate water systems. Eggs were retained in an adult coho salmon which was found For over 20 years, scientists faced a toxic mystery:dead prior to spawning.coho salmon returning to urban streams and rivers in the Puget Sound region were dying before they could lay their eggs. The culprit was unknown, but it seemed linked to toxic chemicals running off our roads and highways.Ivy observed mortality rates of up to 80 percent in juvenile coho exposed to unfiltered stormwater during three representative storms.Understanding the timing and intensity of rain events and contaminated surges of flow, helps predict when streams are most likely to contain dangerous levels of toxins. The research being done to address water quality impacts on salmonids in runoff-impaired watershedsVolunteers survey Walker and Miller Creeks by walking along fills a critical knowledge gap in our understanding ofthe stream and counting and measuring salmon.the effects of roadway runoff and 6PPD-quinone on salmon and trout and the effectiveness of filtration at reducing/eliminating mortality. These studies inform the identification of mortality hotspots caused by contaminant exposure and improve understanding of road runoff impacts across multiple life stages of salmon. Testing filtration to reduce or eliminate mortality caused by the toxic chemical 6PPD-quinone will inform stormwater management and treatment practices for urban streams.This research benefits salmon and trout-bearing streams throughout Puget Sound. At a local level, this research is both timely and critically important for Miller Creek,A rubber preservative commonly used in car tires might likely a small coastal tributary that supports coho and chumbe the cause for dozens of dead coho salmon.salmon, resident and sea-run cutthroat trout, and may periodically provide non-natal rearing habitat for juvenilegroups. As Seattle continues to grow and traffic increases, Chinook salmon. Community-driven salmon surveys sinceaddressing stormwater contaminants like 6PPD-q 2011 have documented high rates of adult coho pre-spawnbecomes an urgent environmental and public health mortality associated with fall storm events and pollutedpriority, and the public can get involved through programs road runoff Investigating storm events and road runofflike the Community Salmon Investigation program and impacts to salmon and trout and filtration effectivenessother citizen science groups that have been extremely are high priorities in this watershed. valuable in the research that WSU and UW are doing. The discovery of 6PPD-quinone and its lethal effects onBy protecting watersheds like Miller Creek. Its not salmonids has shifted how we understand stormwaterssolely about salmon; its about preserving the integrity impact on our environment. It serves as a call toof the entire ecosystem that supports biodiversity, action, not just for scientists, but also for city planners,community health, and overall quality of life for future policymakers, and the public through citizen sciencegenerations in this region.26 Normandy Park City SceneSpring 2025'