In this bonus episode of Rethinking EHS, host Beatrice Bizarro speaks with Ivy Liu (Terrapex Canada) to explore the impact of 6PPD-quinone on coho salmon populations in the Pacific Northwest. The conversation highlights how a common tire additive transforms into a toxic compound in the environment, causing widespread mortality in sensitive fish species and signalling broader water quality issues linked to urban runoff.
In this bonus episode of Rethinking EHS, Beatrice Bizzaro and Ivy Liu take a deeper dive into the environmental consequences of 6PPD-quinone, focusing on its devastating effects on coho salmon. As a keystone and indicator species, coho salmon play a critical role in ecosystem health and provide an early warning signal for water pollution.
The episode explains how 6PPD, a widely used tire additive, reacts with ozone to form a highly toxic byproduct that enters waterways through stormwater runoff. This has led to acute and often rapid mortality events in salmon populations, particularly in urban streams, with significant ecological, cultural, and economic implications.
Ultimately, the episode underscores the urgent need for improved stormwater management, stronger regulatory action, and the development of safer chemical alternatives. It calls on organisations and regulators to take proactive steps to reduce pollutant release and better protect aquatic ecosystems.
-----
Timestamps:
00:06 – Introduction & episode overview
00:43 – Why coho salmon are key indicator species
03:28 – How 6PPD enters waterways
05:04 – Why research is concentrated in the Pacific Northwest
06:09 – Key takeaways and urgency for action
07:28 – Salmon life cycle and vulnerability
09:25 – “Canary in the coal mine” explained
11:45 – Closing reflections
-----
Sponsor:
Rethinking EHS is brought to you by the Inogen Alliance. Inogen Alliance is a global network of 70+ companies providing environment, health, safety, and sustainability services, working together to provide one point of contact to guide multinational organizations to meet their global commitments locally. Visit inogenalliance.com to learn more.
-----
Links
https://www.Inogenalliance.com/resources
https://www.Inogenalliance.com/podcast
Beatrice on LinkedIn https://www.linkedin.com/in/beatrice-bizzaro/
Ivy on LinkedIn https://www.linkedin.com/in/ivy-liu-p-geo-qpra-4a797520/
Produced by https://www.madcontent.co.nz
Transcript
1
00:00:06,100 --> 00:00:12,000
Beatrice:
Hello everyone and welcome to Season 3 of Rethinking.
2
00:00:12,000 --> 00:00:20,000
Beatrice:
The EHS Global Goals, Local Delivery
and Inogen Alliance podcast.
3
00:00:20,000 --> 00:00:28,000
Beatrice:
My name is Beatrice Designer,
Water Stewardship Technology Lead at HPC Italy,
4
00:00:28,000 --> 00:00:32,200
Beatrice:
and your host for today’s bonus episode.
5
00:00:32,230 --> 00:00:43,140
Beatrice:
I’m joined by Ivy from Terrapex.
Thanks for being here again, Ivy.
6
00:00:43,190 --> 00:00:55,200
Beatrice:
Why is coho salmon used
as an early warning indicator?
7
00:00:55,220 --> 00:01:07,150
Ivy:
Coho salmon are extremely sensitive.
8
00:01:07,150 --> 00:01:14,010
Ivy:
It helps to view them in the broader
Pacific Northwest salmon context.
9
00:01:14,030 --> 00:01:26,000
Ivy:
They’re among the most affected species
by 6PPD-quinone contamination.
10
00:01:26,000 --> 00:01:38,000
Ivy:
Salmon are vital to ecosystems —
as predators, prey, and nutrient recyclers.
11
00:01:38,000 --> 00:01:50,000
Ivy:
They also act as indicator species,
reflecting overall water quality.
12
00:01:50,220 --> 00:02:05,000
Ivy:
Coho salmon are especially useful indicators
because their response is acute and repeatable.
13
00:02:05,000 --> 00:02:21,110
Ivy:
This makes them key for identifying
urban runoff contamination.
14
00:02:21,130 --> 00:02:28,190
Ivy:
6PPD-quinone has been recognised
as a global contaminant since 2023.
15
00:03:28,210 --> 00:03:36,000
Beatrice:
How does it enter surface water?
16
00:03:36,000 --> 00:03:44,080
Ivy:
It comes from 6PPD,
a chemical used in car tyres.
17
00:03:44,080 --> 00:03:56,140
Ivy:
When tyres wear down,
particles react with ozone.
18
00:03:56,140 --> 00:04:05,000
Ivy:
This creates the toxic byproduct,
6PPD-quinone.
19
00:05:04,120 --> 00:05:16,000
Beatrice:
Why did research start
in the Pacific Northwest?
20
00:05:16,000 --> 00:05:30,000
Ivy:
Because coho salmon are native there,
and mass die-offs were highly visible.
21
00:05:30,000 --> 00:05:51,000
Ivy:
That triggered strong local research efforts
across universities and institutions.
22
00:05:51,020 --> 00:06:03,000
Beatrice:
What’s the key takeaway
from your work?
23
00:06:03,000 --> 00:06:20,000
Ivy:
The chemical is highly toxic
and shouldn’t be taken lightly.
24
00:06:20,000 --> 00:06:34,000
Ivy:
We urgently need safer alternatives
and better stormwater management.
25
00:07:16,180 --> 00:07:28,140
Beatrice:
Why are salmon especially vulnerable?
26
00:07:28,160 --> 00:07:42,000
Ivy:
They are anadromous —
moving between ocean and freshwater.
27
00:07:42,000 --> 00:08:03,060
Ivy:
This exposes them to risks
across multiple environments.
28
00:08:03,080 --> 00:08:20,000
Ivy:
They hatch in streams, move through estuaries,
then mature in the ocean.
29
00:08:20,000 --> 00:08:41,000
Ivy:
Finally, they return to freshwater
to spawn — often in urban areas.
30
00:09:25,060 --> 00:09:35,060
Beatrice:
What does “canary in the coal mine” mean?
31
00:09:35,080 --> 00:09:50,000
Ivy:
They signal broader water quality issues
caused by urban runoff.
32
00:09:50,000 --> 00:10:07,230
Ivy:
Their response is rapid and often lethal.
33
00:10:08,000 --> 00:10:27,160
Ivy:
Mortality can reach 60–90%,
sometimes within 90 minutes.
34
00:10:27,180 --> 00:10:44,000
Ivy:
Even at extremely low concentrations.
35
00:11:02,110 --> 00:11:20,000
Ivy:
This makes them powerful indicators
of broader environmental contamination.
36
00:11:45,010 --> 00:11:47,230
Beatrice:
Thank you, Ivy.
37
00:11:48,000 --> 00:12:05,000
Beatrice:
Thanks for listening.
Follow the podcast on Spotify, YouTube, LinkedIn and Apple.
38
00:12:05,000 --> 00:12:30,000
Beatrice:
Until next time,
thank you for being part of this community.