Pollutants, such as harmful organic chemicals and metals, enter Puget Sound through a variety of sources, including wastewater, industries, atmospheric deposition, and runoff from urban and agricultural sources. Many chemicals stick to particles in the water and sink, which makes sediment a great record of chemical contamination. Puget Sound sediments trap and can release many of these chemicals, which can make their way up the food chain into the fish that orcas and humans eat. King County (KC) monitors marine sediment chemistry, as part of its Routine Marine Sediment Monitoring Program, to help us better understand what impacts chemical pollution may be having to the bottom of Puget Sound, and how it may be changing due to anthropogenic influences.

This Sampling and Analysis Plan describes the goals, objectives, and study design for the 2025 Elliott Bay Sediment Sampling event, one component of King County’s Routine Marine Sediment Monitoring Program.