Publication Summary

As a component of a three-year cooperative effort of the Washington State Department of Ecology and the National Oceanic and Atmospheric Administration, surficial sediments from 100 locations in central Puget Sound were tested in 1998 to determine their relative quality. The purpose of this survey was to determine the quality of sediments in terms of the severity, spatial patterns, and spatial extent of chemical contamination, toxicity, and adverse alterations to benthic infauna. The survey encompassed an area of approximately 732 km2, ranging from Port Townsend south to Des Moines in the central region of Puget Sound.

As a component of a three-year cooperative effort of the Washington State Department of Ecology and the National Oceanic and Atmospheric Administration, surficial sediments from 100 locations in central Puget Sound were tested in 1998 to determine their relative quality. The purpose of this survey was to determine the quality of sediments in terms of the severity, spatial patterns, and spatial extent of chemical contamination, toxicity, and adverse alterations to benthic infauna. The survey encompassed an area of approximately 732 km2, ranging from Port Townsend south to Des Moines in the central region of Puget Sound.

Data from the chemical analyses indicated that toxicologically significant contamination was restricted in scope to a relatively minor portion of the region. However, sediments from several sampling locations within Elliott Bay and other locations had relatively high chemical concentrations. Data from toxicity tests indicated that many of the samples from inner Elliott Bay, including the lower Duwamish River, and Sinclair Inlet were relatively toxic. Toxicity also was observed in additional samples from locations scattered throughout the region. Wide ranges in several numerical indices of benthic infaunal structure were observed, but the majority of samples had diverse and abundant populations of benthos representative of conditions typical of the area. Eighteen samples in which chemical concentrations were relatively high, toxicity was apparent, and benthic communities appeared to be affected represented 1.1% of the study area. Samples in which chemical contamination and toxicity were observed, but the benthos was relatively abundant and diverse, represented 12.5% of the study area. Samples that were not contaminated, not toxic, and had abundant benthic communities represented 49.1% of the survey area, while samples which displayed either toxicity or chemical contamination (but not both) and abundant benthic communities represented 37.3% of the survey area. Generally, upon comparison, the number of stations displaying degraded sediments based upon the sediment quality triad of data was slightly greater in the central Puget Sound than in the northern Puget Sound study, although the percent of the total study area degraded in each region was similar (1.3 and 1.1%, respectively). In comparison, the Puget Sound sediments were considerably less degraded than those from other NOAA sediment surveys conducted nationwide.