Port Gardner Bay Marine Sediments Data Summaries, Findings, Publications

Everett Harbor and the Snohomish River Delta

The following table contains links to data summaries. (Click on X to open files. Shaded boxes indicate summaries not yet available.)

Year Sampled Station Locations Physical Chemical Toxicity Benthic Invertebrates Sediment Quality Triad Indicators
2012 X X X X X X
2018            
2024            

Findings - 2012

In June 2012, the Washington State Department of Ecology (Ecology) sampled sediments in Port Gardner Bay to characterize sediment quality, as part of the Puget Sound Ecosystem Monitoring Program (PSEMP). The study area covered the subtidal portion of eastern Possession Sound, from Mission Beach to Elliott Point (yellow in map above), including portions of the Port of Everett and the Snohomish River Delta. Surface sediments (top 2-3 cm) from 30 randomly selected locations were analyzed to determine:

  • Concentrations of potentially toxic chemicals
  • Degree of response in laboratory tests of toxicity.
  • Condition of sediment-dwelling invertebrates (benthos).

The sediment contaminant, toxicity, and benthic invertebrate data were rolled up into Ecology’s Chemistry, Toxicity, Benthic, and combined Triad Indices.

  • Overall sediment quality was generally high.
    • Exposure to contaminants was minimum for 80% of the area and low for the remainder.
    • Sediments were non-toxic almost everywhere (93% of the study area).
    • The Triad Index classified sediments as unimpacted or likely unimpacted almost everywhere.
  • Adversely affected benthos were found in one-third (33%) of the study area
  • The Chemistry and Triad Indices met their respective Puget Sound Partnership targets.

Publications

Partridge, V., S. Weakland, M. Dutch, E. Long, and K. Welch. 2014. Sediment Quality in Port Gardner Bay, 2012. Washington State Department of Ecology Publication 14-03-035. 8 pp.

Quality Assurance Project Plan

Dutch, M., V. Partridge, S. Weakland, K. Welch, and E. Long. 2009. Quality Assurance Project Plan: The Puget Sound Assessment and Monitoring Program Sediment Monitoring Component. Washington State Department of Ecology Publication 09-03-121. 98 pp.
Dutch, M., S. Weakland, V. Partridge, K. Welch, and E. Long. 2011. 2012 Addendum to Quality Assurance Project Plan: The Puget Sound Assessment and Monitoring Program/Urban Waters Initiative: Sediment Monitoring in the San Juan Islands and Port Gardner/Everett Harbor. Washington State Department of Ecology Publication 09-03-121-Addendum3. 47 pp.