Toxic Chemicals in Puget Sound photo identifier

Toxic Chemicals in Puget Sound

Pathways

A “pathway” is the route that toxic chemicals travel to reach Puget Sound.

The Toxics Assessment found that polluted surface water runoff, especially during storm events, is the most common pathway toxic chemicals take to reach Puget Sound. When rain hits roofs, roads, and other hard surfaces in our residential, commercial, and industrial areas, it picks up and carries toxic chemicals. This polluted water runs into storm drains and flows — mostly untreated — into lakes, streams, rivers, and eventually Puget Sound.

The Toxics Assessment also found that some chemicals fall directly onto Puget Sound marine waters from the air — called air deposition. Air deposition was the most significant pathway for PBDE flame retardants and some PAHs.

The Toxics Assessment found that wastewater treatment plants generally account for less than 10 percent of the total quantity of toxic chemicals that reach Puget Sound, though they were the second largest pathway for PBDEs. Wastewater treatment plants process municipal wastewater from our sinks and toilets as well as industrial wastewater from factories.


For more information, see Loading Quanitities.

Assessment of Selected Toxic Chemicals in the Puget Sound Basin

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

Factsheet:
Focus on Puget Sound: Puget Sound Toxics Assessment

FAQ:
Frequently Asked Questions