USGS Ecologist Julia David collects water quality data in the lower Stillaguamish Estuary near Stanwood, WA. Data will support a baseline assessment of PAH concentrations in fish in the Stillaguamish River, WA.
Baseline assessment of PAH concentrations in fish from the Stillaguamish River, Washington
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By Washington Water Science Center
September 27, 2023
The Issue:
Polycyclic aromatic hydrocarbons (PAHs) are a class of oil-derived compounds widely distributed in fresh and marine waters. They pose a significant toxicity risk to fish. It can be challenging to pinpoint the source of PAHs found in wild fish populations. PAHs are widespread and come from many sources, so it is hard to determine whether fish exposure is event-related or consistent with background levels.
How USGS will help:
The USGS is conducting a baseline assessment of PAH concentrations in Chinook salmon in the Stillaguamish River for the Stillaguamish Tribe of Indians. Establishing baseline concentrations will allow assessment of the potential future impacts of oil spills, urban growth, and increased traffic.
Background
Twenty billion gallons of crude oil is transported by rail and pipeline annually in Washington State. The state contains over 600 miles of pipeline, including a north-to-south pipeline stretching from Blaine, WA, to Portland, OR. The pipeline route runs through the highly populated Puget Sound region. These crude oil pipelines and rail transport routes pass through multiple watersheds where spills could threaten adjacent or downstream aquatic resources and groundwater.
Sources/Usage: Public Domain. View Media Details
For example, in June 2016, 16 tanker railcars derailed near the Columbia River Gorge National Scenic Area. Approximately 42,000 gallons of crude oil spilled into the Columbia River and ignited a fire. The oil spill illustrates the risk to aquatic habitats crossed by and adjacent to oil pipelines and oil transporting rail lines and to the valued aquatic resources in these habitats that include Endangered Species Act (ESA) listed species such as Chinook and coho salmon, steelhead and bull trout, pacific lamprey, and their prey.
The Stillaguamish River flows from the western foothills of the Cascade Mountains and empties into Puget Sound north of Seattle, WA. It consists of two main forks, the North and South, and has numerous tributaries. The watershed encompasses 700 square miles. The river is home to eight species of salmonids, including ESA-listed Chinook and bull trout.
The area surrounding the lower mainstem of the Stillaguamish River contains several quickly growing medium-sized urban and suburban developments with miles of paved roads and impervious surfaces. In addition, the river is crossed by the Burlington Northern rail line and the Olympic pipeline. These transportation routes carry refined high-viscosity liquids such as gasoline and jet fuel. Additionally, the Trans-Mountain pipeline spur, which carries crude oil, sits next to Skagit Bay, a prime habitat for anadromous fish migrating to or from the Stillaguamish River. This infrastructure creates the potential for an oil spill to impact salmonids and other fish in the Stillaguamish River.
Problem
After any oil or hazardous spill in an aquatic system, the critical ecological question is the relevant ecosystem impacts and the subsequent length of any recovery period. Previous measurements and baseline data collected leading up to the spill are essential for answering this question. If baseline data doesn’t exist, several assumptions must be made about the ecological condition before the spill, which often includes selecting non-impacted reference sites for sampling and comparison. Reference sites that truly mimic impacted habitats are often hard to find, and the uncertainty of the resulting data hampers the accurate determination of environmental impacts.
Polycyclic aromatic hydrocarbons (PAHs) are considered the most toxic component of an oil spill. Baseline data measuring PAHs in fish tissues is scarce, partly due to the assumption that PAHs generally do not bioaccumulate in fish. Although fish readily metabolize PAHs, the fish convert them into water-soluble compounds (metabolites). These metabolites are stored in bile before excretion in the gastrointestinal tract, where they can be reabsorbed, creating a “recirculating reservoir” of PAH exposure and increased opportunity for adverse effects, such as DNA damage. Thus, PAH metabolites are a sensitive indicator of ongoing and recent exposure to oil and PAHs.
Objectives
The project involves collecting PAH metabolite concentrations in fish bile from three locations along the Stillaguamish River. Concentrations will indicate baseline conditions when no recent major oil spill has occurred. Additionally, we will assess PAH concentration in sediments to determine if there is a persistent source of PAHs within the watershed.
Relevance and Benefits
The Stillaguamish Tribe of Indians relies on healthy salmon populations in the Stillaguamish River for subsistence and commercial fishing. Anthropogenic land uses in the watershed have the potential to negatively impact this vital resource. The baseline data collected in this study will equip the Tribe with the data needed to assess impacts after an oil spill and to determine trends in subsequent sampling.
Additionally, the study will help inform the relative PAH exposure to two different fish species: salmonids and sculpin. Correlating the PAH metabolite concentrations between the species may allow scientists to use sculpin as a surrogate for assessing exposure. Sculpin, in contrast to salmonids, are not ESA-listed nor prized for their economic and cultural significance. Sampling sculpin is advantageous due to their healthy population numbers, ubiquitous occurrence, ease of capture, and limited fisheries use.
Approach
The Stillaguamish Tribe and USGS sampled juvenile Chinook salmon and sculpin at three river locations using beach seines, during the spring and summer of 2023. Fish were dissected immediately on site and bile ducts and livers were removed for analysis of PAH metabolite equivalents. Liver and bile samples will be sent to the USGS’s Columbia Environmental Research Center for PAH metabolite analysis. In addition, sediment samples were collected at each site for analysis of a suite of PAHs. Results will be reported in 2024.
Water Quality Sampling in the Lower Stillaguamish Estuary
USGS Ecologist Julia David collects water quality data in the lower Stillaguamish Estuary near Stanwood, WA. Data will support a baseline assessment of PAH concentrations in fish in the Stillaguamish River, WA.
The Issue:
Polycyclic aromatic hydrocarbons (PAHs) are a class of oil-derived compounds widely distributed in fresh and marine waters. They pose a significant toxicity risk to fish. It can be challenging to pinpoint the source of PAHs found in wild fish populations. PAHs are widespread and come from many sources, so it is hard to determine whether fish exposure is event-related or consistent with background levels.
How USGS will help:
The USGS is conducting a baseline assessment of PAH concentrations in Chinook salmon in the Stillaguamish River for the Stillaguamish Tribe of Indians. Establishing baseline concentrations will allow assessment of the potential future impacts of oil spills, urban growth, and increased traffic.
Background
Twenty billion gallons of crude oil is transported by rail and pipeline annually in Washington State. The state contains over 600 miles of pipeline, including a north-to-south pipeline stretching from Blaine, WA, to Portland, OR. The pipeline route runs through the highly populated Puget Sound region. These crude oil pipelines and rail transport routes pass through multiple watersheds where spills could threaten adjacent or downstream aquatic resources and groundwater.
Sources/Usage: Public Domain. View Media Details
For example, in June 2016, 16 tanker railcars derailed near the Columbia River Gorge National Scenic Area. Approximately 42,000 gallons of crude oil spilled into the Columbia River and ignited a fire. The oil spill illustrates the risk to aquatic habitats crossed by and adjacent to oil pipelines and oil transporting rail lines and to the valued aquatic resources in these habitats that include Endangered Species Act (ESA) listed species such as Chinook and coho salmon, steelhead and bull trout, pacific lamprey, and their prey.
The Stillaguamish River flows from the western foothills of the Cascade Mountains and empties into Puget Sound north of Seattle, WA. It consists of two main forks, the North and South, and has numerous tributaries. The watershed encompasses 700 square miles. The river is home to eight species of salmonids, including ESA-listed Chinook and bull trout.
The area surrounding the lower mainstem of the Stillaguamish River contains several quickly growing medium-sized urban and suburban developments with miles of paved roads and impervious surfaces. In addition, the river is crossed by the Burlington Northern rail line and the Olympic pipeline. These transportation routes carry refined high-viscosity liquids such as gasoline and jet fuel. Additionally, the Trans-Mountain pipeline spur, which carries crude oil, sits next to Skagit Bay, a prime habitat for anadromous fish migrating to or from the Stillaguamish River. This infrastructure creates the potential for an oil spill to impact salmonids and other fish in the Stillaguamish River.
Problem
After any oil or hazardous spill in an aquatic system, the critical ecological question is the relevant ecosystem impacts and the subsequent length of any recovery period. Previous measurements and baseline data collected leading up to the spill are essential for answering this question. If baseline data doesn’t exist, several assumptions must be made about the ecological condition before the spill, which often includes selecting non-impacted reference sites for sampling and comparison. Reference sites that truly mimic impacted habitats are often hard to find, and the uncertainty of the resulting data hampers the accurate determination of environmental impacts.
Polycyclic aromatic hydrocarbons (PAHs) are considered the most toxic component of an oil spill. Baseline data measuring PAHs in fish tissues is scarce, partly due to the assumption that PAHs generally do not bioaccumulate in fish. Although fish readily metabolize PAHs, the fish convert them into water-soluble compounds (metabolites). These metabolites are stored in bile before excretion in the gastrointestinal tract, where they can be reabsorbed, creating a “recirculating reservoir” of PAH exposure and increased opportunity for adverse effects, such as DNA damage. Thus, PAH metabolites are a sensitive indicator of ongoing and recent exposure to oil and PAHs.
Objectives
The project involves collecting PAH metabolite concentrations in fish bile from three locations along the Stillaguamish River. Concentrations will indicate baseline conditions when no recent major oil spill has occurred. Additionally, we will assess PAH concentration in sediments to determine if there is a persistent source of PAHs within the watershed.
Relevance and Benefits
The Stillaguamish Tribe of Indians relies on healthy salmon populations in the Stillaguamish River for subsistence and commercial fishing. Anthropogenic land uses in the watershed have the potential to negatively impact this vital resource. The baseline data collected in this study will equip the Tribe with the data needed to assess impacts after an oil spill and to determine trends in subsequent sampling.
Additionally, the study will help inform the relative PAH exposure to two different fish species: salmonids and sculpin. Correlating the PAH metabolite concentrations between the species may allow scientists to use sculpin as a surrogate for assessing exposure. Sculpin, in contrast to salmonids, are not ESA-listed nor prized for their economic and cultural significance. Sampling sculpin is advantageous due to their healthy population numbers, ubiquitous occurrence, ease of capture, and limited fisheries use.
Approach
The Stillaguamish Tribe and USGS sampled juvenile Chinook salmon and sculpin at three river locations using beach seines, during the spring and summer of 2023. Fish were dissected immediately on site and bile ducts and livers were removed for analysis of PAH metabolite equivalents. Liver and bile samples will be sent to the USGS’s Columbia Environmental Research Center for PAH metabolite analysis. In addition, sediment samples were collected at each site for analysis of a suite of PAHs. Results will be reported in 2024.
Water Quality Sampling in the Lower Stillaguamish Estuary
USGS Ecologist Julia David collects water quality data in the lower Stillaguamish Estuary near Stanwood, WA. Data will support a baseline assessment of PAH concentrations in fish in the Stillaguamish River, WA.
USGS Ecologist Julia David collects water quality data in the lower Stillaguamish Estuary near Stanwood, WA. Data will support a baseline assessment of PAH concentrations in fish in the Stillaguamish River, WA.