This document summarizes research on the impacts of urban stormwater runoff on coho salmon and potential solutions. The research has found that: (1) urban stormwater runoff is causing high rates of pre-spawn mortality in coho salmon returning to spawn in Puget Sound streams; (2) exposure to chemicals in road runoff is sufficient to kill coho salmon; and (3) green stormwater infrastructure like bioretention cells can prevent this toxicity when used to treat stormwater runoff. The research aims to identify the specific chemicals causing the mortality so they can be replaced or controlled through solutions like enhanced stormwater treatment.

1. Salmon and Stormwater Runoff
Jenifer McIntyre
WSU School of the Environment | WA Stormwater Center| Puyallup, WA
SEHAB | Online| Nov 16, 2020

2. Research PARTNERS & SUPPORTERS

3. Goals of WSU Research Program
1) Understand chemical impacts of
stormwater runoff to aquatic animals
2) Develop and test solutions that will
prevent aquatic toxicity from
stormwater runoff

5. Longfellow Creek 2005
Longfellow Creek 2002
Coho dying prematurely in urban creeks
Pipers Creek 2002

6. Coho Salmon Spawning in Urban Areas
High rates of
pre-spawn
mortality in
urban creeks
Widespread &
recurrent

7. Des Moines Creek 2004
Longfellow Creek 2003
Weight-of-evidence points to stormwater runoff
Longfellow Creek 2012
Recurrent Die-Offs of Adult Coho Salmon Returning to
Spawn in Puget Sound Lowland Urban Streams
Nathaniel L. Scholz1
*, Mark S. Myers1
, Sarah G. McCarthy2
, Jana S. Labenia1
, Jenifer K. McIntyre1
, Gina M.
Ylitalo1
, Linda D. Rhodes1
, Cathy A. Laetz1
, Carla M. Stehr1
, Barbara L. French1
, Bill McMillan3
, Dean
Wilson2
, Laura Reed4
, Katherine D. Lynch4
, Steve Damm5
, Jay W. Davis5
, Tracy K. Collier1
1 Northwest Fisheries Science Center, NOAA Fisheries, Seattle, Washington, United States of America, 2 Department of Natural Resources and Parks, King County, Seattle,
Washington, United States of America, 3 Wild Fish Conservancy, Duvall, Washington, United States of America, 4 Seattle Public Utilities, City of Seattle, Seattle,
(2011, 6(8):e28013)

8. Spromberg & Scholz. 2011. Integrated Env. Assess.Manag.
Rapid extirpations predicted for coho salmon
Even low rates of pre-spawning
mortality projected to cause
local population extirpation

9. 9
This is not a FOREST

11. 11
An urban stormwater outfall
West Seattle underwater footage by Laura James (www.diverlaura.me)

12. Road Runoff
>15,000 AADT
Seattle

13. Collecting Road Runoff

14. road runoff
clean well water
Experimentally exposing coho spawners to road runoff

15. Unexposed (3.5 h) Stormwater-exposed (3.5 h)
Spromberg
et
al.
2016.
J.
Applied
Ecology
… Induces pre-spawn mortality

16. Urban road runoff is sufficient to kill coho salmon
Road runoff: All die within 24 h of exposure
Adult spawners Juveniles
Alevin
McIntyre et al. 2015. STOTEN Spromberg et al. 2016. J Appl. Ecol. Chow et al. 2019. Aquat Tox.

17. Transfer to clean water does
NOT prevent mortality
60 120 180 240 300 360 min
Surfacing
(sec
/
15
min)
600
Urban stormwater runoff affects coho behavior
Juveniles
Discrete > Continuous > Disequilibrium > Moribund
Chow et al. 2019. Aquat. Tox.

18. High dilutions and short durations needed
Road runoff did NOT kill coho when:
• Diluted ≥98% with clean water (24 h)
• Only exposed for an hour (11% runoff)
Prat et al. Unpublished data
Most coho deaths took place in clean
water following the runoff exposure
Urban streams can be equivalent to 15%
road runoff

19. Urban stormwater runoff affects coho blood
Symptomatic fish: Osmoregulatory imbalance & hemoconcentration
Adult spawners
McIntyre et al. 2018. Environ. Pollution

20. Urban stormwater runoff affects coho blood
Blair et al. Submitted to CJFAS
Stephanie Blair
Ph.D. student
WSU SOE
• Injected fluorescent dye
into fish heart
• Rinsed all blood from fish
• Froze and sectioned body
• Measured fluorescence
from leaked plasma
Evans Blue dye
injected into
heart
Gills clear after
perfusion

21. Urban stormwater runoff affects coho blood
Hemoconcentration linked to plasma leaking from vascular system
Blair et al. Submitted to CJFAS

22. Sensitivity to runoff varies among salmon species
McIntyre et al. 2018. Environ. Pollution
O. keta
O. kisutch
Chum showed no mortality, no behavior changes, and no blood changes

23. Sensitivity to runoff varies among species
O. nerka
O. mykiss
O. tshawytscha
O. kisutch
O. keta
French et al. In Prep

24. What in stormwater makes salmon sick?

25. The chemistry of
stormwater runoff
Metals
phthalates
Some
pesticides
Some hydrocarbons
Thousands of unique chemicals are
present in urban road runoff
Du et al. 2017. Env. Sci. Processes and Impacts
Relatively few of them are identified
Peter et al. 2018. ES&T
The chemicals that we know don’t
appear to cause the observed
toxicity
Spromberg et al. 2016. J. Appl. Ecol.
Some
?

26. Predictive Mapping
Feist et al. 2017. Ecol Applications
Contributing Land Uses
Increasing PSM
Higher rates of
mortality
associated with
roads & traffic

27. Which are most toxic? Which contribute most to toxicity?
Tire Wear Exhaust Brakes Washer Fluid
Automobile Leaks:
• Fuel
• Engine Oil
• Brake Fluid
• Engine Coolant
• Transmission Fluid
Leaks
What are vehicle sources of chemicals in road runoff?

28. Vehicle sources
of pollution
Urban runoff
that kills coho
Urban streams
that kill coho
Non-target high resolution mass spectrometry time-of-flight
Peter et al. 2018. ES&T

29. Peter
et
al.
2018.
ES&T
Hierarchical cluster analysis

30. Assessing the importance of tires to runoff toxicity
9-tire mix
Particle sizes: 0.2 ± 0.3 mm2 (0.002- 23.9 mm2)

31. • Graduate
students
• Electric planer
• Carbide
grinding disk
• Respirators
• VOC filter
Generating Tire Tread Particles for Testing

32. Generating 9-Tire Powder Mix for Testing
9 Tires
7 used
2 new
Ground to
powder
Combined
in equal-
weights

33. Making a Leachate from Tire Particles
Mix tire particles
with glass beads in
stainless steel
column
Cover column with
a filter to keep
particles in column
Run clean water
through column
for 24 h

34. Are tires an important source of toxicity in urban runoff?
Compare effects of stormwater and chemicals leaching from tires:
1. Does tire leachate cause acute mortality in coho?
2. Coho uniquely sensitive (chum NOT affected)?
3. Similar pathophysiology for tire leachate as stormwater?

35. Identifying the causal toxicant(s) from tires
Steps (Toxicologist-
Interpreted)
1. Find a fraction that does
NOT kill coho salmon
2. Identify chemical properties
limited by that fraction
3. Identify chemicals missing
from that fraction
4. Confirm the toxicity of
identified toxicants
Anal. and Bioanal. Chem., 2003, 377(3): 397-407
Effect-directed analysis (EDA)

36. Tire Leachate Fractionation Studies
Leaching Methods
1. 9-tire mix
2. 1 g/L tire leachate
3. 0.5 L/min for 24 h
Screening Methods
1. Juvenile coho; 30 L
5 fish/fraction; 24 h
2. Negative control
(lab water)
3. Positive control
(250 mg/L leachate)

37. Tire Leachate Fractionation Overview
Fractionation Method Target Property
Sand Filter Particulates
Aeration Volatility
Chelation Metals
Cation Exchange Resin Cations
Heating Thermal stability
Reverse phase chromatography Polarity
Zhenyu Tian & Kathy Peter – postdocs with Dr. Ed Kolodziej at UW-Tacoma

38. Tire Leachate Fractionation Summary
Fractionation Method Prevented Mortality? Conclusion about Contaminants
Acutely Lethal to Coho
Sand Filter No Not particulate
Chelation No Not a metal
Cation Exchange Resin Yes but… Positively charged?
Cation Exchange Resin Only 1st fraction Somewhat non-polar
Heated (80℃) with head space YES Volatile or thermally instable
Heated (80℃) no head space No Thermally stable
Coarse aeration No Not easily volatilized
Fine aeration YES – but no recapture Volatile & oxidizable
Reverse phase fractionation YES – eluted with EtOH Moderately polar
Zhenyu Tian & Kathy Peter – postdocs with Dr. Ed Kolodziej at UW-Tacoma

39. Tire Leachate Fractionation Summary
Primary causal contaminant is
a transformation product of a
common ingredient in tires

40. What do we
do about it?

41. Story Map of Coho Pre-Spawn Mortality
http://tinyurl.com/yysuuh6y

42. Identifying Coho Salmon

43. Become a Citizen Scientist!
Where in
Puget Sound
watersheds
are coho
spawners
dying
prematurely?

44. Report pre-spawn mortality

45. Solutions to stormwater pollution: Source Control
Ongoing collaboration to identify the
responsible contaminant(s)
Ongoing conversation with
USTMA about whether
chemical(s) can be replaced

46. Solutions: Green Stormwater Infrastructure

47. GSI Research at WSU/WSC
Rain Gardens
Permeable Pavement
Mesocosms

48. GSI Research at WSU/WSC
Drainage layer
Bioretention
soil medium

49. 2” mulch
18” bioretention soil media
(60% sand : 40% compost)
12” drainage layer (gravel aggregate)
underdrain
cap slotted 2” PVC bulkhead 2” ball valve
Bioretention Filtration System
Washington State Department of Ecology (2014)
Stormwater Management Manual of Western Washington

50. Portable bioretention system constructed
24” bioretention medium
60% sand:
40% compost
mulch
55-ga
drum
Slotted
underdrain
12” drainage layer

51. Clean well water
Can bioretention prevent coho PSM?
100% Normal 100% Symptomatic ??????
Treated runoff
Untreated runoff

52. Well water (4 hr) Filtered stormwater (4 hr)
Unfiltered stormwater (4 hr)
All 4 fish alive at 24 hr
All 4 fish alive at 24 hr 0 of 4 fish alive at 24 hr
Bioretention treatment of stormwater prevents toxicity
Prevents acute mortality in spawners, juveniles, and alevin
Videos: https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12534
Spromberg et al. 2016. J. Applied Ecology

53. Bioretention filtration prevented alevin mortality
Episodic exposure of coho embryos to runoff
0
0.2
0.4
0.6
0.8
1
Control R50 R100 F100
Proportion
Alive
(Day
64)
Bioretention
McIntyre et al. In Prep.
* *

54. Bioretention Performance: Amendments
• 2-yr installation
• BSM + Plants + Fungi
• Real-time input from I-5
• Quarterly monitoring:
• Hydrology
• Chemistry
• Toxicology
• Plants improve
hydraulic
conductivity
• Fungi retain
moisture &
reduce leaching
of nutrients and
metals
Alex Taylor
M.S. 2018
WSU BSysE

55. PAH and bacteria treatment in bioretention
Objectives:
1) Evaluate novel bioretention
amendments (biochar and fungi) to
improve removal of organic
contaminants:
• Polycyclic aromatic hydrocarbons
• Bacterial pathogens
Chelsea J. Mitchell
PhD student, SOE
Wine cap mushroom
(Stropharia rugosannulata)
Biochar
(Pine & fir
feedstock)
2) Investigate fate and biodegradation of PAHs in
bioretention columns with and without amendments

56. Biofiltration Performance: Roadside Treatments
Compost
Topsoil
Water
WSU
Ben Leonard
Ph.D. student
WSU SOE
UW
Ed Kolodziej
+ 2 postdocs
Compost-Amended
Bioswale

57. Bioretention Performance: Longevity
Lane Maguire
M.S. Student
WSU SOE
Accelerated Aging:
• 10 water years across 2-yr study
• Assess chemical and biological
performance at end of every
water year
Research questions:
• What depths of bioretention are
necessary to treat runoff?
• For how long are they effective?

58. Bioretention Performance: BURitos
Bioretention Urban
Retrofit of
stormwater
detention ponds
Compost-filled
berms to
encourage more
treatment of road
runoff before enters
urban streams
Kit Paulsen
City of Bellevue

59. Permeable
Pavements
• Toxic chemicals in effluent?
• Provide chemical treatment?
• Perform differently with carbon
fibers incorporated?
• Perform differently over time?
• Asphalt or concrete
• Clean water or runoff
• With or without C fibres
Chemistry and toxicology over time

60. Salmon and Stormwater Summary
• Coho salmon spawners die prematurely at high rates in urban creeks
• Road runoff is sufficient to cause the acute mortality
• Very high dilutions of road runoff are necessary to prevent mortality
• Affected fish die quickly of unknown causes
• Juvenile and alevin coho are similarly sensitive
• Pacific salmon sensitivity: coho > steelhead > chinook
• Coho embryos show sublethal effects, similar to other developing fish
• Urban stormwater runoff is a very complex chemical mixture
• High-traffic roads are the best correlated land use with coho PSM
• Tire wear particles are an important source of toxicity
• Bioretention is a green stormwater infrastructure that can prevent toxicity
• More work is needed before we can best answer ‘how much and where’?
• Spread the word about coho urban mortality syndrome via StoryMap!

61. This is not a forest

62. Questions?
Nathaniel.Scholz@noaa.gov
Jay_Davis@fws.gov
Koloj@uw.edu
Starkj@wsu.edu
Jen.McIntyre@wsu.edu