I’m pretty used to reading headlines detailing the latest health issues plaguing our freshwater fish. He comes with the territory as an ecotoxicologist working on the health of North America’s relatively abundant, but certainly not infinite, freshwater supplies.
However, I was struck by the recent announcement that Sen. Ron Wyden (D-Ore.), along with other state and federal legislators, is calling for an investigation into the toxic contamination of salmon in the Pacific Northwest. It fits into a larger question about salmon health that has had my community in an uproar for the past few years.
Surprisingly, it all starts with cars.
It’s no secret that Americans love cars. In fact, in 2022 there were 290.8 million vehicles registered in the United States alone, 19 percent of the world total. That’s almost one car per person. And while we’re always weighing the benefits and conveniences that cars bring us against the potential impacts on the environment, it seems there was an effect of a chemical we didn’t even know existed, that we weren’t even aware of. Until very recently.
The science is quite complicated, but let me summarize.
Rubber tires used on automobiles contain chemicals used to strengthen them and help them withstand the road and the elements. It’s like a preservative that extends the shelf life of a grocery product in the supermarket, but for tires.
As these protectants break down (due to the elements), one of them forms a newly discovered chemical called 6PPD-quinone which can then be washed into freshwater lakes, rivers, etc., with some life-threatening consequences. wild that resides inside.
This may include impacts on freshwater fish species that many communities depend on, such as rainbow and brook trout and, of course, coho salmon, whose recent mass die-offs off the West Coast had puzzled researchers for a long time. weather.
This is important for many reasons. Coho salmon are popular with recreational anglers, but they are also an environmentally important species within aquatic ecosystems, so a change in their populations could have knock-on effects throughout the food chain.
But the problem is that we just don’t have the evidence to prove that in any way. Research so far has looked at the impact of 6PPD-quinone on individual species, but not on a freshwater ecosystem as a whole.
When tires leak into a river or lake and kill coho salmon, what does that do to the in-lake populations that coho salmon feed on? And so what does that mean for lake populations in general? And the chemistry of the water? And such and such.
Our freshwater ecosystems are intricate and complex, and a change in population can have a multitude of ripple effects that we can’t even anticipate.
That’s why we need more research, on this relatively understudied chemical, ideally in a real-life setting that can reveal the myriad of shocks running through the system.
And while Oregon Wyden’s call for an investigation is much needed and welcome, only once we have a full picture of what tire runoff is doing to our fresh water can we make informed policy decisions that will protect our health. of one of our most important resources for generations to come.
José Luis Rodríguez Gil is a research scientist at the International Institute for Sustainable Development for the Experimental Lakes Area