Happy Feet Articles - 48. 6PPD-quinone in Lakes

6PPD-quinone in Lakes

Katherine Kim

For decades, scientists have been concerned about automobile pollution. Tires are made up of natural and synthetic rubber, but they also contain hundreds of other ingredients like metals. Globally, approximately 1 billion end-of-life tires are generated each year. In the United States alone, about 280 million tires are discarded annually. As car tires wear, chemicals and microparticles are released into the environment, leading to the deaths of salmon in Washington’s streams.

Although researchers had suspected that a chemical had been the cause of these deaths in salmon, it was only until 2020 when a team identified the chemical. 6PPD-quinone is in virtually every tire in the world, and it entered the Washington streams. This chemical is found everywhere. Waterways, the air, and even in the human body. Within 45 minutes of exposure to this chemical, salmon are killed almost instantly, demonstrating the impact of the 6PPD-quinone chemical.

Coho salmon are federally listed as either threaten or endangered along the US west coast. Throughout the years, these species have greatly diminished and face an array of threats. “Most species of salmon are experiencing a serious threat at least somewhere in their native range,” said Jenifer McIntyre, an assistant professor of aquatic toxicology at Washington State University. “One of my lifelong goals would be to make our cohabitation with them more sustainable. Salmon are beautiful and delicious and important to ecosystems but they are becoming a rare thing for people to experience.”

Efforts have been made to reduce the impact of tires on bodies of waters and their ecosystems. "6PPD plays a crucial role in the safety of tires on California's roads and, currently, there are no widely available safer alternatives," said Karl Palmer, a deputy director at the state's Department of Toxic Substances Control. "For this reason, our framework is ideally suited for identifying alternatives to 6PPD that ensure the continued safety of tires on California's roads while protecting California's fish populations and the communities that rely on them."

Works Cited

Lewin, Brent, et al. “Our car tires are poisoning salmon—and maybe us, too.” National Geographic, 26 March 2025, https://www.nationalgeographic.com/animals/article/salmon-tires-health-chemical. Accessed 8 April 2025.

“Pollution from car tires is killing off salmon on US west coast, study finds.” The Guardian, https://www.theguardian.com/environment/2020/dec/03/coho-salmon-pollution-car-tires-die-off.

Robbins, Jim. “Tire toxicity faces fresh scrutiny after salmon die-offs.” CBS News, https://www.cbsnews.com/news/toxic-tires-6ppdq-auto-pollution-fish-kills/.