PM09 Sediment Quality Assessment Cases
Exhibit Hall
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(PM148) Sediment Metals Verification Study for Sinclair and Dyes Inlets, Washington.
Kohn, N1, Johnston, R2, Miller, M1, Evans, N1, Kirtay, V2, Ayers, B2, Beckwith, B3, Wright, J3, Blakley, N4, 1 Battelle Marine Sciences Laboratory, Sequim, Washington, USA2 Space and Naval Warfare Systems Center, San Diego, California, USA3 Puget Sound Naval Shipyard & Intermediate Maintenace Facility, Bremerton, Washington, USA4 Washington State Department of Ecology, Olympia, Washington, USA
ABSTRACT- This study was conducted to address metal contaminants listed on the State of Washington 303(d) list of impaired waters, specifically those waters located in Sinclair and Dyes Inlets near Bremerton, Washington. Significant cleanup and source control activities have been conducted in the Inlets since the data supporting the 303(d) listings were collected. The primary objectives of the study were to document the current sediment metal concentrations in Sinclair and Dyes Inlets and evaluate whether the sediment concentrations exceed sediment quality criteria for metals. Hydrodynamic modeling has shown significant water exchange and sediment transport between Sinclair and Dyes Inlets. Another objective was to provide metals data to support contaminant loading and transport modeling throughout Sinclair and Dyes Inlets. A total of 160 sediment samples from Sinclair Inlet, Dyes Inlet, Port Orchard Passage, and Rich Passage were screened for copper, lead, and zinc using X-Ray Fluorescence (XRF). About 40 samples (25%) were selected for confirmatory metals analysis by ICP-MS. Most of the confirmatory samples were located in Sinclair Inlet, where metal concentrations were historically highest. The XRF results for copper, lead, and zinc correlated well with standard analytical method (ICP-MS) results. Linear regression was used to estimate metal concentrations from the XRF screening data for the 120 samples that were not analyzed by ICP-MS. Measured or estimated concentrations of lead did not exceed the Washington State sediment quality standard (SQS). Two samples exceeded the copper SQS and nine exceeded the zinc SQS; all but one of these were located very close to the shipyard piers. Sediment metals concentrations are markedly reduced since source control and sediment cleanup actions. The study outcomes will help prioritize management actions where sediment remains a source of water quality impairment.
Key words: marine water quality, sediment quality, metals, TMDL