San Juan Islands Marine Sediments Data Summaries, Findings, Publications

San Juan Islands

The following table contains links to data summaries.  (Click on X to open files. Zip files will need to be extracted into another folder. Shaded boxes indicate summaries not yet available.)

Year Sampled Station Locations Physical Chemical Toxicity Benthic Invertebrates Sediment Quality Triad Indicators
2002-2003 * * * * * *
2012 X X X X X X
2022            

*Available upon request.

The San Juan Islands Sediment Quality Triad Index (PDF) offers a one-page summary of these findings.

Puget Sound Marine Sediment Indicators is a webpage that describes the Sediment Quality Triad Index, a method to rate the health of marine sediments.

Findings 2012

In June of 2012 the Washington State Department of Ecology (Ecology) sampled 40 sites to evaluate sediment quality in the San Juan Islands with the sediment quality triad of chemistry, toxicity, and benthic (sediment-dwelling) invertebrate community structure. Results are compared with those from a similar survey in 2002-2003, conducted with the same methods, to determine whether sediment quality had changed. In summary:

  • Sediment quality did not change significantly over the 10-year period.
  • Overall sediment quality in the San Juan archipelago in 2012 was high.
    • No sites had chemicals measured above (not meeting) Washington State Sediment Quality Standards. Exposure to chemical contaminants for the entire study area was characterized as minimum with the Sediment Chemistry Index.
    • Sediment toxicity assessed in the laboratory with a test of amphipod survival indicated that 92% of the study area had sediments characterized by the Sediment Toxicity Index as non-toxic; the remaining 8% of area had low toxicity. No samples exhibited moderate or high toxicity.
    • The Triad Index classified sediments as unimpacted or likely unimpacted almost everywhere (92% of the area studied).
  • Benthic invertebrate assemblages were judged with the Sediment Benthic Index to be adversely affected by stressors in 58% of the study region, likely a function of the natural, physical environment.

Publications

Partridge, V., S. Weakland, M. Dutch, and K. Welch. 2014. Sediment Quality in the San Juan Islands, Changes over a 10-Year Period. Washington State Department of Ecology Publication 14-03-034. 8 pp.
Long, E., S. Aasen, M. Dutch, K. Welch, and V. Partridge. 2008. Sediment Quality Assessment of the Bays and Inlets of the San Juan Islands, eastern Strait of Juan de Fuca, and Admiralty Inlet, 2002-2003. Washington State Department of Ecology Publication 08-03-030. 142 pp + appendices.
Long, E., S. Aasen, M. Dutch, K. Welch, and V. Partridge. 2008. Sediment Quality in the Bays and Inlets of the San Juan Islands, Eastern Strait of Juan de Fuca, and Admiralty Inlet (2002-2003). Washington State Department of Ecology Publication 08-03-031. 4 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., V. Partridge, S. Weakland, 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.