Sediment Quality in Puget Sound Year 2 - Center for Coastal ...

Examination of the next three strata (7, 9, and 10) including three smaller, shallow embayments
adjacent to the central basin (Figures 39 and 40), revealed no stations in which all three triad
parameters appeared to be impacted. None of the three stations (124-126) located in Port
Madison (stratum 7) (Figure 39) displayed any toxicity or chemical contamination. These
stations were located at 28-45m depth, and were comprised of silty-sand (14-26% fines).
Infaunal communities were both abundant (637-852 individuals) and taxa rich (73-93 total taxa),
and shared 9 of their 10 dominant species.
Sediments from stations 130-132, located in stratum 9, Eagle Harbor (Figure 40), were collected
from 1 l-14m depths, and ranged in composition from silty sand (station 132,20% fines) to
mixed sediments (stations 130 and 13 1,44% and 80% fines, respectively). All three stations
displayed significant toxicity with the cytochrome P450 HRGS assay, but no chemicals exceeded
state or national guidelines. Sediment from these stations however, did exhibit strong petroleum
(from all 3 stations) and sulfur (from stations 13 1-132, only) odors, and were olive gray in color,
indicating possible chemical contamination andlor anoxic conditions. Infaunal indices showed
few consistencies among the three stations, although the benthic infaunal assemblages did share
3 of their 10 dominant species, including the pollution-tolerant polychaete, Aphelochaeta sp. N1.
Although it is possible that the infaunal communities were responding to some type of
unmeasured chemical contaminant or adverse natural condition (e.g., low dissolved oxygen) in
the sediments, andlor were associated with the significant toxicity displayed, the triad of
evidence pointing to pollution-impacted stations was not complete at these three stations.
The three shallow stations (stations 133-135; 27 - 47 m depth) in stratum 10, to the south and
west of Blake Island (Figure 40), were composed of predominantly silt and clay particles (8 1 -
94% fines). None of the three stations had chemical concentrations in the sediments exceeding
state or national guidelines, although station 134 displayed significantly reduced amphipod
survival, and station 135 displayed significant cytochrome P450 HRGS toxicity response. No
clear pattern of correspondence could be seen between these parameters and the infaunal
assemblage composition, with all three stations possessing relatively abundant and taxa rich
assemblages, and sharing 4 of their dominant species.
Examination of the thirty stations from the 10 strata west of Bainbridge Island, including Liberty
Bay, and Dyes and Sinclair Inlets, indicated that ten stations (stations 148, 15 1, 160- 165, 170,
171) had both significant toxicity results and elevated chemical contamination. Eight of these ten
stations were located in Dyes and Sinclair Inlets. Eleven of these thirty stations (stations 142,
145, 147, 149, 150, 152, 154-156, 166, 169) had no significant results; none were located in
Sinclair Inlet, and only one in Dyes Inlet (Figures 39,41).
Examination of stations in strata 15 and 16 (west of Bainbridge Island) (Figures 39 and 4 1 )
indicated high levels of 4-methylphenol and benzyl alcohol at stations 148 and 15 1, respectively.
Both stations also displayed significant toxicity with the cytochrome P450 HRGS assay. Depths
of the 6 stations in these two strata were shallow, ranging from 6 to 35m. Sediment types for
these stations included silt-clay at stations 148, 15 1, and 153 (90%, 95%, and 87% fines,
respectively), mixed at station 150 (5 1% fines), silty sand at station 152 (22 % fines), and sand at
station 149 (6% fines). Infaunal indices and dominant species composition (i.e., 5 shared
dominant species) were similar among the three stations with silt-clay sediments, suggesting that
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