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

grain size, rather than the toxicity and chemical composition of the sediments, had a large
influence on community structure at these stations. 111 addition, station 148 (goyo fines,
significant cllemistry and toxicity) displayed infaunal indices and species compositio~~ (i.e.,
sharing 8 of 10 domi~la~lt species) similar to station 150 (5 1% fines), which had 110 significant
toxicity results or elevated chemical co~lcentratio~ls. Stations 149 (6% fines) and 152 (22 % fines)
displayed no significant toxicity results or elevated chemical concentratio~~s, and little similarity
to any of these 6 stations in their community composition and infaunal indices, probably due to
their sediment grain size composition.
The sediments from all six stations (160-165) in strata 19 and 20 (Sinclair Inlet) were composed
primarily of silt-clay (87-96% fines), and were collected from 8.6 to 13.5m depths. These
sediments also had a strong sulfur smell, and were gray to black in color, possibly indicating
anoxic conditio~~s. All stations exhibited mercury conce~ltrations exceeding state and, with the
exception of station 16 1, national standards, accompa~~ied by significant toxicity wit11 the
cytochrome P450 HRGS assay at all statio~ls, and significa~~tly reduced urchin fertilizatio~l at
stations 160 and 165. All of the statio~ls had relatively high benthic infaunal abundance (except
for station 160, which also had the highest toxicity level based on percent urchin fertilization)
and relatively high taxa richness, but low Swartz's Domina~lce Index (2-7 taxa). The benthic
commu~~ities at stations 160, 16 I, 163, and 164 were dominated by Aphelochaeta species N I. At
station 160, however, total abundance and abundance of all taxa groups was significantly
reduced. Statio~ls 162 and 165 were dominated by Ezdo~~ella paczjka and Anzphiodia species.
These 3 taxa, along wit11 the decapod crustacean Pi~z~zixu schnzitti, were present in 5 of the 6
statiolls in Sinclair Inlet. It is possible that the composition of the infaunal commu~~ities at these
6 statio~ls, dominated by these 4 taxa, was a result of adverse chemical and toxicological impact
from the sediments at these stations, indicati~~g triad support for classification of these stations as
impacted by pollution. It is also possible, however, that the infaunal composition at these statio~ls
was the result of other environmental factors that have not been measured, such as ~~aturally
occurri~lg anoxic conditions in the sediments. In comparison, station 13 1, in Eagle Harbor,
possessed many cl~aracteristics similar to the stations in Sinclair Inlet, including olive gray
sediments with a strong sulfir odor, sl~allow depth (1 lm), high percent fines (80?40), significant
toxicity with the cytochrome P450 HRGS assay, and relatively high benthic infaunal abundance
and taxa richness but low Swartz7s Domi~lance Index (8 taxa). The dominant species list
included both Aplzelochueta sp. Nl and E~~lorella pacijka. No chemistry concentrations
exceeded state or national standards, however, unlike the stations in Sinclair Inlet, which might
indicate that the possible anoxic conditio~~s at these stations were a naturally occurring factor
influencing community structure.
Stratum 21, located in the Port Washington Narrows (Figure 41), contained three stations (166-
168) in 18m, 8.2m, and 26m of water, respectively. Sediments at stations 166 and 167 consisted
primarily of sand (7% and 8% fines, respectively), while station 168 consisted of silty sand (35%
fines) and had a strong sulfur smell. Station 166 displayed no significant toxicity results or
elevated chemical concentrations, while station 167 had higllly significant amphipod mortality
and urchin fertilization was sig~~ifica~ltly reduced. Station 168 displayed both significant urchin
and cytochrome P450 HRGS toxicity results. Stations 166 and 167 shared similar infaunal
indices, possibly due to their similar sediment grain size composition. All three stations shared
two dominant taxa, the mollusc Alvania conzpacta and the polychaete Aphelochaeta sp. Nl. In
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