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Toxic Chemicals in Puget Sound

Puget Sound Toxics Assessment:
Frequently Asked Questions (FAQ)

Report Overview and Methods

Report Findings

Actions and Next Steps


Report Overview and Methods

What is the Puget Sound Toxics Assessment?

The Assessment of Selected Toxic Chemicals in the Puget Sound Basin: 2007-2011 – also known as the Puget Sound Toxics Assessment – is the most recent look at what is known about toxic chemical pollution in the Puget Sound region. The Puget Sound Toxics Assessment is the final element of a multi-year, multi-agency effort called Control of Toxic Chemicals in Puget Sound that started in 2006.

While the Control of Toxic Chemicals study has many elements, its primary focus was to understand where toxic chemicals come from, how they reach Puget Sound, and the potential harm they cause to people, fish, and other living things. The study describes:

  • The 17 toxic chemicals and chemical groups studied that pose a risk to the health of people, fish, and Puget Sound.
  • The harmful effects of these toxic chemicals on the environmental health of Puget Sound.
  • The sources where these toxic chemicals come from, such as roofing materials, pesticide use, and drips and leaks from vehicles.
  • The “pathways” that toxic chemicals travel to reach Puget Sound, such as surface water runoff, air deposition, and wastewater treatment plant discharges
  • The quantity – or “loading” – of each chemical that is entering Puget Sound.
  • Priorities for actions to reduce and control pollution from the key sources.

What geographic area did the study focus on?

The Puget Sound Toxics Assessment focused broadly on the Puget Sound basin. This is a large geographic area that includes all the land and connected freshwater lakes, streams and rivers as well as the marine waters of Puget Sound. The Puget Sound basin covers Clallam, Island, Jefferson, King, Kitsap, Mason, Pierce, San Juan, Skagit, Snohomish, Thurston, and Whatcom counties.

What toxic chemicals did the study focus on and why?

While businesses and individuals currently use thousands of chemicals, scientists narrowed the study to address a manageable number of chemicals. The assessment focused on 17 toxic chemicals and chemical groups based on their potential to harm the health of people, fish, and the Puget Sound ecosystem.

These chemicals reach Puget Sound through a variety of pathways. Some of these chemicals are representative of larger classes of toxic pollutants that are likely present in Puget Sound waters.

Chemicals in the assessment include:

  • The metals arsenic, cadmium, copper, lead, mercury, and zinc.
  • Three categories of PAHs (polycyclic aromatic hydrocarbons), which are components of creosote-treated wood, wood smoke, and vehicle exhaust.
  • Petroleum-based compounds such as motor oil, hydraulic fluids, gasoline, diesel and jet fuels and other petroleum products.
  • Flame retardants such as PBDEs (polybrominated diphenyl ethers).
  • Phthalates, a family of chemicals commonly used to make plastics flexible and durable.
  • PCBs (polychlorinated biphenyls) and DDT (dichlorodiphenyltrichloroethane), which were banned years ago but are still present in the environment.
  • Dioxin, particularly PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans).
  • Triclopyr, a commonly used weed killer.
  • Nonylphenol, a compound often found when detergents break down and in industrial air emissions.

See more information on the chemicals in this study.

How do we know that the information in the Puget Sound Toxics Assessment is accurate?

The Department of Ecology worked with a team of regional experts and commissioned an independent review to ensure that the scientific methods and approaches used in the study are reliable. The study identified a range of quantities, and the findings represent our best estimates for the amounts and sources of toxic chemicals reaching Puget Sound.

Report Findings

Are toxic chemicals the main pollution threat to Puget Sound’s health?

Polluted surface water runoff, which can contain a variety of pollutants, poses the main pollution threat to Puget Sound’s health. Researchers emphasize that other pollutants in surface water runoff–in addition to the toxic chemicals examined in this study–also contribute to Puget Sound’s health problems. Many of the same actions needed to reduce toxic chemicals may also reduce these other pollutants. Other broad categories of pollution that reach Puget Sound in polluted surface water runoff include:

  • Nutrients from fertilizers and animal manure cause algae blooms that can reduce oxygen levels in the water. Fish need oxygen dissolved in water. In areas with low levels of dissolved oxygen, fish and other marine life can become stressed and die or be forced to flee their habitat.
  • Bacteria from animal wastes and failing septic systems can make people sick and shellfish unhealthy to eat.
  • Sediments can smother aquatic habitats, including fish spawning grounds, and carry toxic chemicals. When runoff scours our river channels, it creates erosion and muddy runoff that carries harmful fine sediments into Puget Sound.

Are the chemicals examined in this study the most harmful chemical pollutants in Puget Sound?

The chemicals examined in this study were chosen because of their high potential to harm the health of people, fish, and the Puget Sound ecosystem. Different pollutants cause different kinds of harm depending on their quantities and circumstances. Because “the dose makes the poison,” the hazard that any given chemical presents depends on how toxic it is and how much enters the Puget Sound environment.

See more information on the harmful effects of the chemicals in this study.

How do these chemicals affect fish and other marine life in Puget Sound?

Fish and other living things in Puget Sound are harmed by many of the chemicals included this study. Recent studies by NOAA Fisheries and U.S. Fish and Wildlife Service found that adult Coho salmon are dying prematurely in large numbers when they return from the ocean to spawn in Puget Sound urban streams. Although the precise cause of these die-offs is not yet known, toxic chemicals in surface water runoff are the most likely explanation. On the other hand, we do understand some of the specific harms caused by chemicals such as:

  • Copper: While people may not be harmed by small amounts of copper, the metal presents a significant threat to salmon and other fish in Puget Sound streams and rivers. Copper interferes with salmon’s sense of smell, which reduces their ability to avoid predators, find their way back to their birthplace to spawn, and find mates. Copper and other metals are often found in surface water runoff.
  • PAHs (polycyclic aromatic hydrocarbons): These chemicals are released by oil leaks, creosote-treated wood, wood smoke, and vehicle exhaust. PAHs that settle in marine sediments cause tumors in marine flatfish, and PAHs from oil spills cause heart defects in young herring and other fish species.
  • Petroleum-related compounds cause problems in many animals and plants. They can poison fish, kill fish eggs, and hinder the feeding and shell-formation of shellfish and other invertebrates. They can damage the skin, lungs, liver, and kidneys of birds and mammals and make them vulnerable to deadly infections by suppressing the immune system. Petrochemicals can reduce the reproductive success of fish, invertebrates, birds, mammals, and even plants, leading to population declines.

See more information on how the toxic chemicals included this study affect humans, fish, and other living things.

Why doesn’t lead appear as a high priority for reduction?

Lead levels measured in Puget Sound rivers and streams seem to pose less of a hazard to fish and other aquatic organisms than copper or PAHs. On the other hand, lead concentrations occasionally exceed water quality criteria in commercial and industrial areas during storm sampling. Because lead persists in the environment and can be taken up in the food chain, the Washington State Legislature has taken action to reduce remaining sources of lead. Since 2011, the use of lead in wheel weights is prohibited, which will help keep lead out of state waters.

Where do these toxic chemicals come from?

The assessment found that key sources of toxic chemicals in Puget Sound include the following:

  • Roofing materials are a major source of copper, cadmium, zinc, and phthalates. For example, the assessment estimates that more than 80 percent of the zinc released from human-caused sources comes from roofing materials.
  • Wood smoke from fireplaces and woodstoves, accounts for about one-third of total PAHs (polycyclic aromatic hydrocarbons) released.
  • Creosote-treated wood–such as pilings, bulkheads, railroad ties, and utility poles–also contributes one-third of PAHs released.
  • Urban and homeowner use of pesticides and fertilizers containing copper accounts for up to one-third of the estimated copper released into Puget Sound.
  • Brake pad wear, roofing materials, and boat paint together also account for about one-third of the estimated copper released to the Sound.
  • Vehicles – both in working order and in need of repair – release a variety of toxic chemicals. Dust from brake pad wear is a key source of copper pollution. Vehicle emissions account for about one-tenth of the estimated total release of PAHs. Motor oil drips and leaks account for two-thirds of the total estimated release of petroleum-related compounds while minor fuel and oil spills contribute more petroleum pollution.

How do these toxic chemicals reach Puget Sound?

Toxic chemicals reach Puget Sound mainly through surface water runoff, air deposition, and wastewater treatment plants. The assessment found that the most common pathway that toxic chemicals take to reach Puget Sound is polluted surface water runoff that flows off residential, commercial, and industrial areas. When rain hits roofs, roads, and other hard surfaces in our developed areas, it picks up and carries toxic chemicals with it. This polluted water then runs into storm drains and flows–mostly untreated–into our lakes, streams, rivers, and Puget Sound.

The assessment also found that some chemicals fall directly onto Puget Sound marine waters from the air. Air deposition is the most significant pathway by which PBDE flame retardants and some PAHs enter the Puget Sound basin.

According to the assessment, wastewater treatment plants generally account for less than 10 percent of the loading that reaches Puget Sound for the chemicals studied. In addition to cities and counties, most factories also discharge their wastewater to wastewater treatment plants.

See more about Pathways.

How big of a problem are wastewater treatment plants?

According to the assessment, wastewater treatment plants generally account for less than 10 percent of the loading that reaches Puget Sound for the chemicals studied. That means we cannot eliminate the toxic chemical problem by controlling only wastewater treatment plants. We also need to reduce the toxic chemicals that come from many scattered and hard-to-trace sources.

In fact, almost everyone uses or produces toxic chemicals. These toxic pollutants come from the roofing materials of our homes, the pesticides and fertilizers we use in our yards and gardens, the oil that drips from our cars, and the smoke from our chimneys and vehicle exhaust pipes. The most common pathway for toxic chemicals to reach Puget Sound is through polluted surface water runoff from urban and suburban areas.

Actions and Potential Next Steps

What are the ways to reduce the threat of toxic chemicals in Puget Sound?

Three key ways to reduce toxic threats are:

  1. Avoid using toxic chemicals in the first place – the smartest, cheapest, and healthiest approach.
  2. Reduce releases by helping people and businesses limit or manage the amount of toxic chemicals that enter the environment.
  3. Clean up contamination after toxics have polluted our air, land, and water. Cleanup is the most costly solution, but it is also necessary where contamination has occurred.
The best way to reduce toxic threats is to prevent contamination in the first place by reducing toxic chemicals at their many sources.

See more about Actions.

What key actions did the assessment recommend to reduce toxic chemicals in Puget Sound?

The most important steps we need to take are to:

  • Improve the way we manage our polluted surface water runoff – especially keeping it from reaching Puget Sound.
  • Reduce the amount of copper washed into our streams and rivers by finding alternatives to copper and other toxic chemicals (including cadmium, zinc, and phthalates) in our roofing materials.
  • Learn more about copper-based pesticides to find ways to reduce their use.
  • Continue to eliminate copper from brake pads and boat paint.
  • Remove creosote-treated wood from Puget Sound beaches.
  • Investigate the impact of creosote-treated utility poles and railroad ties located near water – especially salmon-bearing streams.
  • Work to eliminate petroleum releases–particularly chronic spills, drips, and leaks from our cars, trucks, and boats. One strategy is to invest in more programs like the Automotive Leak Workshops and the Clean Marina Program.

Click here for a full list of potential actions.

How is information in the Puget Sound Toxics Assessment being used?

The assessment will help policy makers set priorities for how to restore and protect Puget Sound. A state agency called the Puget Sound Partnership is responsible for leading the coordinated effort to restore and protect Puget Sound.

The Partnership is responsible for crafting the Puget Sound Action Agenda–the single playbook for prioritizing and focusing recovery and protection efforts by government agencies, scientists, environmental organizations, agricultural organizations, and businesses in the 12 counties that border Puget Sound. The Partnership will use the assessment to help develop prevention and cleanup solutions in the Action Agenda that:

  • Improve the way we manage polluted surface water runoff.
  • Build on current efforts to reduce the amount of copper that enters Puget Sound.
  • Speed up the removal of creosote-treated pilings and bulkheads.
  • Prevent oil spills, including drips and leaks from motor vehicles and boats.

What is currently being done to reduce pollution from industrial sites, boatyards, and marinas?

Tough pollution limits in industrial stormwater permits are helping reduce copper, zinc, and other toxic chemicals in surface water runoff at approximately 1,200 industrial sites. Ecology’s boatyard permit requirements are reducing the copper, lead, and zinc that enter water runoff from boatyard activities. New kinds of marine paint now are being made without copper and other known pollutants.

What’s being done to reduce toxic chemicals in polluted surface water runoff?

Many state and local agencies and other organizations are working to reduce polluted surface water runoff. The Department of Ecology is working on the next generation of proposed stormwater permit requirements to reduce polluted surface runoff in Western Washington. The proposed requirements call for the use of low impact development (LID) where feasible. LID uses ponds, rain gardens, or other measures to mimic the natural environment so water can soak into the ground or be used by plants, reducing runoff. LID allows surface runoff to stay on site instead of flowing into storm drains and waterways.

What is currently being done about the “legacy” chemicals, such as DDT and PCBs, that have been banned but are still present in Puget Sound?

Federal, state, and local governments are working together to clean up sites contaminated with these legacy chemicals. Our best strategy is to continue these cleanup efforts, particularly at sites near rivers and marine areas. DDT and PCBs can take decades to break down.

Who should be responsible for reducing toxic chemicals?

We all share responsibility for the health of the Sound. And we all share responsibility for the pollution that’s created by our cars and trucks, our rooftops, and the chemicals we use in everyday products. So we all share responsibility for restoring Puget Sound to health. If we make good land use decisions today, and control our runoff, the magnitude of this problem will be smaller for future generations.

Are some of these chemicals already banned or restricted?

Yes, the federal government has banned DDT and PCBs. The Washington State Legislature has also made important progress to control many other toxic chemicals in our state. These measures include banning or reducing the allowable uses of pollutants such as:

  • PBDEs (polybrominated diphenyl ethers) in flame retardants.
  • Copper in brake pads and boat paint.
  • Lead in wheel weights.
  • PAHs in coal tar-based pavement sealants.
  • Phosphorus in lawn fertilizers.
  • Bisphenol A (BPA) in baby bottles.

Should copper in pesticides be banned?

We need to learn more about copper in pesticides before we consider such an action. It is important to reduce copper in urban and suburban areas and streams, where concentrations are highest. Reducing copper could mean working to persuade homeowners to voluntarily stop using copper-based pesticides and moss killers while Ecology works with the Washington State Department of Agriculture to study how farmers use these products and whether agricultural use is a problem.

Should the toxic chemicals in roofing materials be banned or controlled?

Ecology is not currently proposing to control the use of toxic chemicals in roofing materials. However, efforts are underway to find out more about which roofing materials contribute the most pollutants and how to make roofing materials less polluting.

What are the most important things individuals can do to help?

We can all be part of the solution by:

  • Driving less. Vehicles are a major source of toxic chemicals from tailpipe emissions, brake pad and tire dust, and fluid leaks and drips.
  • Making informed choices about the products we use every day in our homes and gardens. Avoiding use of toxic chemicals is the best way to protect the health of Puget Sound, ourselves, and our families.
  • Keeping pollutants out of storm drains. Most water that enters storm drains flows directly and untreated to local lakes, rivers, stream, and eventually Puget Sound.
We can actively support community organizations that work to clean up our waters and insist that our elected leaders make reducing toxic threats a priority. Find more tips about how you can help on Ecology’s Washington Waters–Ours to Protect website and on the Puget Sound Partnership’s site, Puget Sound Starts Here.


What does “source” mean?

In the study, the term “source” means an object or activity from which a toxic chemical is initially released into the environment. For example, an initial release of copper occurs from car and truck brake pad wear. When we drive, our brake pads shed small amounts of copper, so brake pads are a source of copper.

See more about Sources.

What does “pathway” mean?

A “pathway” is the route that toxic chemicals take from their source to reach Puget Sound. For example, surface water runoff picks up toxic chemicals from pavement, roofs, and other hard surfaces. Then the polluted runoff flows into the lakes, streams, and rivers that drain to Puget Sound. In this case, surface water runoff is the “pathway” for toxic chemicals entering Puget Sound. This study examined four main pathways: surface water runoff, air deposition, wastewater treatment plants, and groundwater discharge.

See more about Pathways.

What do “surface water runoff” and “stormwater” mean?

Surface water runoff” and “stormwater” are interchangeable terms. They refer to the portion of rain and snow that that does not seep into the ground or evaporate. Instead stormwater runs off pavement, roofs, and other hard surfaces to the nearest waterway or storm drain. As it travels, the runoff collects pollutants that are on the ground or have fallen from the air. Most surface water runoff reaches Puget Sound without any treatment to remove pollutants.

What does “air deposition” mean?

Air deposition” happens when airborne pollutants fall to the earth or into the water. For example, some PAHs (polycyclic aromatic hydrocarbons), a type of toxic chemical, are released from burning wood. These toxic chemicals rise with the smoke into the atmosphere and then fall back to the land or water.

What does “groundwater discharge” mean?

Groundwater discharge refers to the portion of rain and snow that soaks into the ground to become groundwater. Once in the ground, this water travels and eventually is discharged into area streams or directly to Puget Sound.

What does “loading” mean?

The term “loading” refers to the quantity of toxic chemicals reaching Puget Sound in a given time period, such as a day or year. For example, the Department of Ecology estimates that the loading of petroleum-based contaminants into Puget Sound is between 330 and 500 metric tons a year.

See more about Loading Quanitities.

Assessment of Selected Toxic Chemicals in the Puget Sound Basin

Assessment of Selected Toxic Chemicals in the Puget Sound Basin: 2007—2011

Focus on Puget Sound: Puget Sound Toxics Assessment