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

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

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

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

Creator- Samreen Siddiqui, Toxic Contaminated Assessment unit- King County Water and Land Resources Division (DNRP), 201 S Jackson St # 600, Seattle, WA 98104

Full Report - King County. 2024. Chemicals of Emerging Concern in Salmon Spawning and Rearing Habitat. Prepared by Samreen Siddiqui and C. Andrew James, Water and Land Resources Division. Seattle, Washington. March 2024.  DOI 

Funded in part by Washington Department of Ecology (WQNEP-2020-KCWLRD-00049) King County Water and Land Resources Division

Recognition of EPA Funding: This project has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement WQNEP-2020-KCWLRD-00049 to King County.  The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

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.