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

station 168, as with two of the stations in Sinclair Inlet, Apheloclzaeta sp. N1 was found in high
~lu~nbers (1023) in a sl~allow station with a strong sulhr odor, although this station had lower
percent fines (35%) than those in Sinclair Inlet (93% and 87%). Aphelochaeta sp. Nl was also
found in sandy stations 166 and 167, but in much lower densities (29 and 100 individuals,
respectively). Conversely, Alvania conzpacta was found in higher densities at the two sandy
stations (79 and 193, respectively), and in lower numbers (35 individuals) at the silty sand
station. Although there are similarities in the significant toxicity measures and infaunal indices
and species composition among station 168 and stations 161 and 164 in Sinclair Inlet, the lack of
significant cllemistry results does not provide a clear association among triad parameters at these
stations. However, as was speculated for the data from Sinclair Inlet, it is possible that other
environmental measures suc11 as dissolved oxygen concentrations in the sediment pore water and
overlying waters may play a role in influe~~cing infaunal co~nmunity composition at this station.
The three stations in stratum 22, Dyes Inlet (1 69- 17 1) (Figure 4 1 ), consisted of one station (1 69)
with no significant toxicity results or elevated chemical concentrations, and two stations with
both significant levels of chemical coi~tamination and toxicity results. The sample from station
169, collected from 7m, was primarily sandy (8% fines), had no significant toxicity results or
elevated cl~emical concentrations, and displayed extremely high total abundance and species
richness. The high total abundance (1 123 individuals) was due primarily to a large abundance of
the polychaetes Phyllochaetopte~~~~s prolifica (455 individuals), Ci1-ceis sp. (240 individuals), and
a small number of Apl~elochaeta sp. Nl (137 i11dividuals).
Stations 170 and 17 1, located in approxi~nately 13.5m depths, both were co~nposed of a 11ig11
percent silt clay (93 and 88% fines, respectively), and both had dark olive gray or brown
sediments with a strong sulfbr s~nell. Both stations had significant levels of clle~nical compounds
(benzyl alcol~ol and either nickel or mercury), and displayed significant cytocllrome P450 HRGS
toxicity results. These two stations shared 8 of 10 dominant species, including the same four
species that dominated the stations in Sinclair Inlet, the ciustaceans Pirznix~z schnzitti and
E~/dorellci pacifica, the brittle star A~~zphio~iia ~~~~tica(uerie~rta complex, and the polychaete
Aplieloc~zaeta sp. Nl. Similar to station 165 in Sinclair Inlet, the crustacea and brittle stars
dominated the two contaminated and toxic stations in Dyes Inlet, wit11 a much-reduced number of
Aphelochaeta sp. Nl present. As wit11 station 165, it is possible that tlle composition of the
infaunal communities at these two stations, dominated by these four taxa, is a result of the
relatively high contami~lation and toxicity in the sediments at these stations, indicating triad
support for classification of these stations as affected by pollution. It is also possible, however,
that the infaunal coinpositio~~ at these stations may be the result of other enviroi~me~ltal factors
existing at these stations that have not been measured, such as naturally occurri~lg anoxic
co~lditions in the sediments. Alternatively, benthic community effects may also be due to an
unmeasured chemical, or a combination of chemicals that were measured at lower levels.
Examination of the thirty-six stations from the 10 strata in Elliott Bay and the Duwamish
indicated that 22 stations, located primarily along the bay's northeastern shoreline, in both tlle
east and west waterways around Harbor Island, and in the Duwamish Waterway, had both
significant toxicity results and elevated chemical conta~nination. Only two of these thirty-six
stations (stations 175 and 178, both in outer Elliott Bay) had no significant toxicity results and no
elevated clle~nical contamination (Figure 42).
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