
Chemicals of Emerging Concern in Salmon Habitat
This study examines the presence of targeted chemicals of emerging concern in selected salmon spawning and rearing habitats.
Chemicals of emerging concern (CECs) come from many different industrial wastes and products such as soaps, paints, home furnishings, and medicines. This study focuses on five classes of CECs including chlorinated paraffins (CPFs), alkylphenols (APs), alkylphenol ethoxylate (APE) surfactants, polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFAS), and the quinone transformation product of the tire rubber antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine or 6PPD-quinone (6PPD-Q). CECs have been largely overlooked in monitoring programs for stormwater-dominated streams, even though these streams are critical spawning and rearing habitat for salmon. This project aims to identify and quantify CEC concentrations within these vital aquatic ecosystems.
PBDE and PFAS concentrations were all below published effects thresholds for freshwater fish at various life stages. APE and CPFs were rarely detected overall. 6PPD-Q remained above threshold levels (LC50~40 ng/L for Salmon). Detailed results are below locations.
The locations of the current study are marked on the map below
Major Rivers (Blue Label) | Small Creek (Red Label) |
---|---|
Cedar (CDR) River | Juanita Creek at I-405 and 132nd ST |
Duwamish (DWR) River | Little Bear Creek |
Sammamish (RCH, SRO) River | Swamp Creek |
The PBDE concentrations at each site during 3 storms are on the map below
01 / 04
1
PBDE concentrations at Duwamish River (DWR) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
2
PBDE concentrations at Cedar River (CDR) sites for 3 stormwater events
OF1 – outfall 1, OF2 – outfall 2, US – upstream, ADJ - adjacent, D - downstream
3
PBDE concentrations at Sammamish River (RCH) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
4
PBDE concentrations at Sammamish River (SRO) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
The PFAS concentrations at each site during 3 storms are on the map below
01 / 04
1
PFAS concentrations at Duwamish River (DWR) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
2
PFAS concentrations at Cedar River (CDR) sites for 3 stormwater events
OF1 – outfall 1, OF2 – outfall 2, US – upstream, ADJ - adjacent, D - downstream
3
PFAS concentrations at Sammamish River (RCH) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
4
PFAS concentrations at Sammamish River (SRO) sites for 3 stormwater events
US – upstream, ADJ - adjacent, D - downstream
The 6PPD-Q concentrations frequently exceeded the acute effects threshold (LC50~40 ng/L) value for adult and juvenile coho salmon, particularly in the locations adjacent to the outfalls, but did not for Chinook salmon. The 6PPD-Q concentrations at the outfall-adjacent (ADJ) sites exceeded the threshold in 75% (21 of 28) of the sampling events collected, and ~35% (37 of 106) of all samples collected across all events. The LC50 was not exceeded in any of the upstream samples collected in the rivers but was exceeded in 25% of the upstream sites in the streams.
The 6PPD-Q concentrations at each site during 3 storms are on the map below
01 / 08
1
6PPD-Q concentrations at Duwamish River (DWR) sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
2
6PPD-Q concentrations at Cedar River (CDR) sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
OF1 – outfall 1, OF2 – outfall 2, US – upstream, ADJ - adjacent, D - downstream
3
6PPD-Q concentrations at Sammamish River (RCH) sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
4
6PPD-Q concentrations at Sammamish River (SRO) sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
5
6PPD-Q concentrations at Swamp Creek sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
*No bar on the graph indicates it was not detected
6
6PPD-Q concentrations at Little Bear Creek sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
*No bar on the graph indicates it was not detected.
7
6PPD-Q concentrations at Juanita Creek at I-405 sites for 3 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
*No bar on the graph indicates it was not detected
8
6PPD-Q concentrations at Juanita Creek at 132nd St. sites for 4 storm events
The red dashed line indicates LC50~40 ng/L concentration for adult and juvenile coho salmon (Lo et al., 2023 ( DOI )
US – upstream, ADJ - adjacent, D - downstream
*No bar on the graph (Site D3) indicates it was not detected
Non Target Analysis Results
A total of 213 compounds were identified via the non-targeted and suspect screening approaches across all sampling events. Results suggest that samples collected adjacent to the outfalls differed from those collected upstream or downstream. The outfalls appeared to have a localized effect on water quality, but the influence varied among sites.
Table-Identified compounds present at outfall-adjacent sampling locations but not upstream. PNEC – Predicted No Effects Concentration from the European Union NORMAN Ecotoxicology Database. y – compound specifically associated with anthropogenic activities. n – compound not associated with anthropogenic activities. Both y and n can have natural and anthropogenic sources.
Conclusion
While APE, CPF, PBDE, and PFAS detected at low concentrations indicate relatively good water quality and pose minimal threat to aquatic life in this area, monitoring of 6PPD-Q reveals a concerning trend. Concentrations of 6PPD-Q frequently exceed toxicity thresholds for both juvenile and adult coho salmon, particularly near outfalls. Fish that utilize these areas as habitat (either resident or rearing) may be negatively impacted. Concentrations and the number of compounds present were generally higher at the stream locations adjacent to outfalls. Fish in these areas are exposed to a mixture of anthropogenic compounds that likely are absent from upstream or (far) downstream locations. Sampling at the upstream sites indicates the presence of a suite of contaminants in most systems investigated, suggesting the potential for chronic exposures. By implementing advanced monitoring systems and increasing stormwater treatment, we can significantly improve water quality, fostering healthier habitats for resident aquatic life.
Data Visualization
Power BI Report