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

Eight samples collected along the shoreline of Elliott Bay (I 15, 176, 179-1 84) had highly
contaminated and relatively toxic sediments. Sediment guidelines for mercury, several PAHs,
butyl be11zy1 phthalate and 4-metl~ylphenol were exceeded in one or more of these stations. The
most extreme case was the sediment from station 184, which exceeded seven ERM and seven
SQS values. At all eight statio~ls, significant toxicity was observed in at least two of the tests.
Cytocl~rome P450 HRGS enzyme induction was very high (> 107pglg) at stations 1 15 and 182-
184, and the urchin fertilization tests were significant at a11 stations except 18 I. Despite the
presence of relatively high chemical concentrations and the occurrence of toxicity in the
laboratory tests, the benthic indices suggested an abundant and diverse benthic community at
seven of these eight stations (i.e., all except station 115). Total abundance at these seven stations
ranged from 457 to 876; taxa richiless ranged from 69 to 113. Evenness values were between
0.73 1 to 0.833, while the Swartz's Dominance Index (SDI) values ranged from 12 to 27. Many
of the dominant species, however, were orga~~isms known for their tolerance to pollutio~~,
including Pai-vilz~cina ten~lisc~~lpta, E~ip/zilo~nedes prodz~cta, Scoleto17za luti, Axinopsida
seri-icata, Pr"ionospio steenstr~qi, and ApJ~elochaeta species N 1. Tlle infaunal commu~~ity at
station 11 5 had both significant cllemistry and toxicity results, and an infaunal community
composition which suggested triad support for classificatio~~ of this station as impacted by
pollutio~~. Total abunda~~ce at this station was higher than at the other slloreline statio~ls (I 161
i~~dividuals), but taxa ricl~ness was depressed (43 taxa), and evenness and SDI values were
extremely low (0.255, 1 taxon). The infaunal community was dominated by the pollutiontolerant
polychaete Aphelochaeta sp. Nl, had 110 echinoderms or miscellaneous taxa, and very
few arthropods.
Relatively high chemical conce~ltrations occurred in five of the twelve stations in the middle of
Elliott Bay (185, 186, 188, 194, and 196). Up to five sediment guideli~les were exceeded at each
of these stations, and mean ERM quotients ranged from 0.4 to 1.5. Amoi~g these five stations,
the sediments at station 188 were most contaminated, primarily with several PAHs. The mean
ERM quotient in this sample was 1.5. Cytocllroine P450 HRGS enzyme inductio~~ was
significantly high (20 to 153 pglg) in all five samples, but none of the other toxicity tests had
significant results. Total abu~~da~lce, taxa richness, evenness, and SDI values for two of these
statio~ls (stations 185 and 186) were relatively lligll, indicating moderately abundant and diverse
communities, with 3 species shared between the stations' top 10 dominant species, including
Axinopsida ser-ricata, E~iphilomedes prod~lcta, and Levinsenia gracilis. These two stations
displayed infaunal community structure that appeared to be o111y modestly influe~lced by the
chemical andlor toxicological contamination of the sediments. Tlle other 3 stations in mid-Elliott
Bay, however, displayed infau~lal indices that are more strongly suggestive of possible triad
corresponde~lce with the chemistry and toxicity results. Tlle infaunal indices at stations 188, 194,
and 196 displayed high total abundance and taxa ricl~ness values (456-825, and 42-67,
respectively), but lowered evenness and SDI values (0.45 1-0.539, and 2-51? and supported
communities with 4 shared dominant species, including Axinopside se~-ricata, Levinsenici
gracilis, Aricideu lopezi, and Scoleto~na luti. There also were few arthropods and echinoderms
(i.e., the typically more pollution-sensitive taxa) in these samples.
All seven stations sampled in the vici~lity of Harbor Island (I 14, 197-202) had elevated
concentrations of trace metals aildlor a number of organic compounds and other toxicants.
Toxicity was significant in the amphipod survival at station 202 (90.1 1% of controls), in the
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