Publication Summary

The 1990 Marine Sediment Monitoring Task was conducted by the Washington State Department of Ecology in conjunction with the Puget Sound Water Quality Authority and other state agencies as a component of the Puget Sound Ambient Monitoring Program. This report includes sediment chemistry and amphipod bioassay data from 50 stations and benthic infauna community data from 35 stations.

The appendices for this report is Publication No. 92-47a.

The 1990 Marine Sediment Monitoring Task was conducted by the Washington State Department of Ecology in conjunction with the Puget Sound Water Quality Authority and other state agencies as a component of the Puget Sound Ambient Monitoring Program. This report includes sediment chemistry and amphipod bioassay data from 50 stations and benthic infauna community data from 35 stations.

The top two centimeters of sediment from three to five grab samples at each station were composited, homogenized, and analyzed for toxicity using amphipod bioassays, and for the presence of metals, semi-volatile and volatile organic compounds, and pesticides/PCBs. Five replicate grab samples were collected at each station for analysis of benthic infaunal communities as well.

Sediments from Stations 34 (Sinclair Inlet) and 35 (Dyes Inlet) exceeded state sediment quality standards for mercury. Concentrations of metals from all other stations were below state standards.

The highest concentrations of volatile organic compounds were found at Station 5 in Samish Bay and Station 38 in East Passage.

Concentration of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs) were highest at Station 40 at the mouth of City Waterway. When normalized to total organic carbon, the concentration of LPAHs at Station 40 exceeded state standards. Concentrations of beta-coprostanol were highest at Station 41 adjacent to the Tacoma wastewater outfall. One base and two acid extractable compounds were detected above quantitation limits, but no concentrations of these compounds were above state standards. The PCB Aroclor 1254 was detected at Station 12 (Port Townsend) and 33 (Elliott Bay). With the exception of p,p'-DDE at Station 33, no pesticides were detected.

After factoring in the effect of grain size, sediment from three stations [(Stations 20 (Port Susan), 43 (Carr Inlet), and 105R (Outer Eld Inlet)] in the 1990 survey were characterized as toxic from the results of amphipod bioassay analysis.

Total abundance of benthic infauna (which did not pass through a 1.0 mm mesh sieve) ranged from 66.3 at Station 3 (Strait of Georgia) to 2184.3 at Station 41 (Blair/Sitcum Waterways) and the number of taxa ranged from 14 at Station 3 to 92 at Station 47 (Case Inlet). Decreased abundances of pollution tolerant species and increased diversity of Stations 30 (Eagle Harbor), 33 (Elliot Bay), and 40 (City Waterway) may indicate improving conditions for benthic infauna at these stations.