Toxic Chemicals in Puget Sound photo identifier

Toxic Chemicals in Puget Sound


The Toxics Assessment provides estimated volumes for toxic chemicals released in the Puget Sound basin. The term “source” means a human-caused object or activity from which a toxic chemical is initially released to the air, land, and waters in the entire Puget Sound basin.

The Puget Sound basin is made up of 2,800 miles of inland marine waters, 2,500 miles of marine and freshwater shorelines, and 19 river drainage basins. It includes the 12 counties that border Puget Sound — Clallam, Island, Jefferson, King, Kitsap, Mason, Pierce, San Juan, Skagit, Snohomish, Thurston and Whatcom.

Not all toxic pollutants reach Puget Sound and the waters that drain to it. Environmental processes such as dilution, deposition and degradation can reduce concentrations of toxic pollutants as they move away from their sources. “Loading Quantities” are the amount of a chemical estimated to reach Puget Sound waters every year from a particular pathway.

The total estimated amount of toxic chemicals released from all sources to the Puget Sound basin typically will be a greater number than the Loading Quantities figure.

The major sources of toxic pollutants are more concentrated in urban and suburban areas. Developed lands such as residential, commercial, and industrial areas were found to contribute the highest concentrations of pollutants.

The Assessment found that toxic chemicals are released from many scattered and hard-to-control sources throughout Puget Sound, ranging from chemicals leaching from roofing materials to motor oil drips and leaks from our cars and trucks. Many products we use every day — such as detergents, plastics, and pesticides — add to the toxic chemicals reaching our waters.

  • The majority of cadmium and zinc released from human-caused sources come from roofing materials
  • Unlike most of the other chemicals evaluated, human-caused sources for arsenic are relatively small compared to loading to Puget Sound. The largest arsenic sources include air emissions, chromated copper arsenate-treated wood and roofing materials.
  • Urban and homeowner use of pesticides and fertilizers containing copper accounts for up to one-third of the estimated release to the Puget Sound region. About another one-third was equally divided between brake pad wear, roofing materials, and boat paint.
  • Wood smoke—from fireplaces and woodstoves—accounts for about one-third of total PAH releases. Another one-third is estimated to come from creosote-treated wood such as pilings and bulkheads, railroad ties, and utility poles. Vehicle emissions account for about one-tenth of the estimated total release.
  • Motor oil drips and leaks account for two-thirds of the total estimated release of petroleum-related compounds.
  • Emissions from burning trash at home (burn barrels) account for about three-quarters of the total dioxins (PCDD/Fs) released.
Some of these chemicals have already been controlled or banned. While DDT and PCBs were banned years ago, they break down so slowly that they continue to cycle in the environment, which makes them very difficult to control.

Finding alternatives has reduced the use of other chemicals. In Washington, lead has been banned in wheel weights, which are now made from steel and other less toxic metal compounds. In addition, copper is being phased out of brake pads and eliminated from boat paint in Washington. On the other hand, we still use many products that contain copper, lead, and other harmful chemicals.

Total estimated releases and largest sources for each chemical

(1 metric ton is approximately 2,200 pounds)
Chemical Estimated total release in
Puget Sound basina
(metric tons per year)
Major sources
Petroleum 9,200
  • Motor oil drips and leaks, and improper disposal of used oil.
  • Gasoline spillage during fueling.
Zinc 1,500
  • Roofing material leaching.
  • Vehicle tire abrasion.
Lead 520
  • Ammunition and hunting shot use.
  • Loss of fishing sinkers and wheel weights.
  • Roofing material leaching.
  • Aviation fuel combustion.
Total PAHs (polycyclic aromatic hydrocarbons) 310
  • Woodstoves and fireplace combustion emissions.
  • Vehicle combustion emissions.
  • Creosote-treated pilings, railroad ties and utility poles.
Copper 180-520
  • Pesticide use on urban lawns and gardens.
  • Residential plumbing component leaching.
  • Brake pad abrasion.
  • Roofing material leaching.
  • Vessel anti-fouling paint leaching.
Triclopyr 150
  • Herbicide use on crops and golf courses.
Phthalates 34
  • Personal care products.
  • Polymer (primarily PVC) off-gassing.
  • Industrial, commercial, and institutional air emissions.
  • Roofing material leaching.
Total PCBs 2.2
  • Electrical equipment spills and leakage.b
Cadmium 0.96
  • Roofing material leaching.
Mercury 0.54
  • Consumer product improper disposal.
  • Crematoria and industrial plants' air emissions.
Total PBDEs 0.68
  • Furniture, computer monitors, and other components of residential and commercial indoor environments.
Arsenic 0.79
  • Industrial air emissions.
  • CCA-treated wood leaching.
  • Roofing material leaching.
Nonylphenolc 0.18
  • Industrial, commercial, and institutional air emissions.
PCDD/Fs 0.000009d
  • Backyard burn barrels.

a The study area which includes Puget Sound, the U.S. portion of the Straits of Georgia and Juan de Fuca and the entire U.S. portion of the watershed for Puget Sound and the Straits.
b Estimate is highly uncertain.
c Sources were not fully assessed.
d Expressed as Toxic Equivalents (TEQs).

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

Frequently Asked Questions