Every fall more than half of the coho salmon that return to Puget Sound’s urban streams die before they can spawn.
Now a team led by researchers at the University of Washington Tacoma, UW and Washington State University Puyallup have discovered the answer.
But researchers started noticing that, especially after a big rain, returning salmon were dying before they could spawn.
In addition, a study led by McIntyre found that a solution made from tire wear particles was highly toxic to salmon.
Researchers used a multi-step chemical separation process to narrow down the list of possible salmon-killing culprits from thousands of chemicals to one.
We knew that the chemical that we thought was toxic had 18 carbons, 22 hydrogens, two nitrogens and two oxygens.
But when 6PPD reacts with ozone, the researchers found that it was transformed into multiple chemicals, including 6PPD-quinone (pronounced “kwih-known”), the toxic chemical that is responsible for killing the salmon. »
