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Recommendation: 47

Status: Pending

Identify and mitigate increased threats to Southern Residents from contaminants due to climate change and ocean acidification. Prioritize actions that proactively reduce exposure where the increased impacts are expected to be most severe.


Action 1

Identify vulnerabilities of existing stormwater and wastewater infrastructure to sea-level rise, flooding, and other high-flow events. Repair, adjust, or mitigate at facilities with higher risks.

Action 2

Identify and prioritize the timely clean-up and remediation of legacy (persistent) toxics and waste sites that are likely to be exposed by sea-level rise, flooding, and high-flow events caused by climate change.

Action 3

Include the impacts of a changing climate and ocean acidification as criteria when developing a prioritized list of chemicals of concern for orcas.

Action 4

Address new contaminants entering marine and inland waters due to the increase in wildland fires associated with climate change. These contaminants include polycyclic aromatic hydrocarbons (PAHs) from smoke, flame retardants, and increased runoff from erosion.

Action 5

Ensure that the National Pollutant Discharge Elimination System permit processes are adaptable and responsive to climate-related impacts.

Action 6

Support the Washington Department of Ecology’s ongoing nutrients work and initiatives, recognizing the co-benefits of addressing nutrients to improve climate resiliency and mitigation efforts in Puget Sound and the Columbia Basin.

Action 7

Treat increased stream temperature resulting from climate change as a pollutant that creates potentially deadly conditions for juvenile salmon and returning adults. Mitigate the increase by expanding riparian vegetation and through other means to moderate temperatures.

Implementation Details

As climate change increases precipitation, flooding, runoff, and sea-level rise, additional work is needed to address increasing levels of contaminants in the state’s waters. Nutrient loadings will increase with these events and exposure to other toxics could increase as well. More toxics will accumulate in the food salmon and orca eat.

In addition, the increased quantity and intensity of flows due to climate change are highly problematic, impacting the hydrology of basins and water systems and destroying the habitats of forage fish and Chinook salmon.

In the near term, efforts to address this threat should focus on the following:

  • Identifying stormwater and wastewater infrastructure and other facilities, including legacy waste sites, most at risk.
  • Taking action to mitigate those risks. Actions include prioritizing and adapting stormwater retrofits to account for the impacts of climate change, accelerating clean-up of toxics and waste sites, modifying or moving treatment facilities to withstand sea-level rise and increased flooding, and increasing protection for low-lying infrastructure facilities (without hardening adjacent shorelines). Over time, agencies will need to monitor how more rainfall, sea-level rise and flooding, and warmer temperatures and ocean acidification affect contaminants in the ecosystem, and address future conditions.


  • To address PAHs and other contaminants associated with increased wildfire smoke and suppression, support the efforts of the Washington Department of Natural Resources, U.S. Fish and Wildlife Service, and other agencies to identify and implement effective management and mitigation strategies.
  • Accelerate the investments and activities to improve forest health and reduce wildfire risks being undertaken by the two agencies to ultimately reduce the intensity and extent of large catastrophic fires and associated smoke as well as the consequent need for flame retardants.
  • With salmon and other wildlife becoming more likely to get diseases in warmer water, targeted toxics reduction strategies should remain a focus for Southern Resident recovery. Additionally, the State should work to better understand emerging toxics threats to determine how effects might be amplified and synergized with changes in climate, water temperature, and chemistry.
  • Include climate change considerations in the National Pollutant Discharge Elimination System permit process. Increase the resiliency of wastewater treatment plants and combined sewer overflows and stormwater facilities to maintain treatability during sea-level rise, extreme flooding, and high-flow events.

Nutrient Management

Regarding nutrient management, Ecology recommends the following:

  • Developing a National Pollution Discharge Elimination System permit framework for wastewater treatment in Puget Sound.
  • Developing a watershed nutrient management model and decision support tool.
  • Collecting high-quality nutrient data in watersheds to fill key knowledge gaps related to baseline conditions.

These actions will address current threats from nutrient loadings to the health of the Puget Sound ecosystem, salmon, and orcas, as well as future increases that will result from climate-driven impacts.

Recent Progress

Climate change and ocean acidification continue to be important considerations in mitigating threats to Southern Residents. Some of this work is identified under Recommendations 30-33, 39, 40, and 44.

More details may be found in the progress reports in the resources library.