(Vancouver) Wildlife conservation groups have written to Canada’s Environment Minister calling for a review of a chemical used in tire manufacturing because they say its degradation is harmful. linked to the mass death of coho salmon.
Peter Ross, senior scientist at the Raincoast Conservation Foundation, says the mystery of coho deaths in urban waterways persisted for years, until a 2020 study uncovered the role of a particular chemical used in tire rubber.
Mr. Ross says the study published in Science, a leading academic journal, found that a chemical known as 6PPD causes degradation that is extremely toxic to coho. He says the study showed toxic concentrations of 6PPD after rain fell in watersheds in the Seattle area in the northwest United States, suggesting it was running off roads and in streams.
Raincoast, Watershed Watch Salmon Society and the Pacific Salmon Foundation, all based in British Columbia, are asking Ottawa for an assessment of the suspected chemical under the Canadian Environmental Protection Act.
A letter sent this week to Environment Minister Steven Guilbeault reminds him that the Government of Canada assessed 6PPD in 2018, concluding that it posed a moderate hazard at high exposure, but that the screening did not take into account the degradation of the product.
Peter Ross says a growing body of research links the breakdown substance 6PPD to the deaths of coho salmon when the fish return from the Pacific Ocean to spawn.
The breakthrough came after scientists conducted research for 20 years, studying every potential culprit, from hydrocarbons to parasites to road salts. Peter Ross observed that these scientists eventually discovered that a previously undocumented chemical was the culprit.
Peter Ross notes that it is very difficult to establish cause and effect relationships between a single pollutant and the health of salmonids, because these fish are exposed to many thousands of different chemicals and pollutants over the course of their lives.
Several groups in British Columbia are currently working on monitoring 6PPD in the waterways of southern Vancouver Island, in particular.