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

oth nickel and benzoic acid, 44 samples had at least one chemical concentration greater than an
SQS value (25.2% of the area) and 36 samples had at least one concentration greater than a CSL
value (2 1.1 % of the area).
Summary
The spatial extent of chemical contamination, expressed as the percent of the total study area,
was determined for the 54 compounds for which chemical guidelines or criteria exist. Twenty of
these compounds were measured at levels that were below the SQS and CSL guidelines, and
were at or below the ERM guidelines, for all 100 stations sampled in central Puget Sound.
Thirty-four (33 excluding nickel) were measured at or above at least one of the guideline values
in at least one station. For 29 of these 34 compounds (including arsenic, zinc, LPAHs, HPAHs,
phthalate esters, PCB congeners, 1,4-dichlorobenzene, and dibenzofuran), the spatial extent of
chemical contamination represented less than 1% of the total study area and was confined to the
stations sampled in the urbanlindustrialized areas of Elliott Bay and the Duwamish River. Four
of the five remaining compounds were measured above guideline levels in greater than 1% of the
study area, including mercury (1.1 1 - 1.98%, Dyes and Sinclair Inlets, Elliott Bay), nickel (1.3 1%,
Liberty Bay, Bainbridge Island, Dyes Inlet), 4-methylphenol (23%, Port Townsend, Possession
Sound, Central Basin, East Passage, Bainbridge Island, Elliott Bay, and the Duwamish River),
and benzyl alcohol (0.47-1.67%, Bainbridge Island, Elliott Bay, and the Duwamish River).
Again, the majority of these compounds exceeding criteria values were located in samples
collected from urbanlindustrialized locations. High concentrations of benzoic acid were found in
about 8 1 %, located around the central Puget Sound study area.
Relationships between Measures of Toxicity and Chemical Concentrations
The associations between the results of the toxicity tests and the concentrations of potentially
toxic substances in the samples were determined in several steps, beginning with simple,
non-parametric Spearman-rank correlation analyses. This step provided a quantitative method to
identify which chemicals or chemical groups, if any, showed the strongest statistical relationships
with the different measures of toxicity.
Toxicity vs. Classes of Chemical Compounds
Spearman-rank correlation coefficients (rho) and probability (p) values for the four toxicity tests
versus the concentrations of four different groups of chemicals, normalized to the respective
ERM, SQS, and CSL values, are listed in Table 15. None of the correlations were significant for
tests of amphipod survival. hi this study, significant statistical correlations between amphipod
survival and chemical concentrations would not be expected because percent survival was very
similar among most samples. Results of the Microtox tests were correlated (Rho = 0.37, pO.01)
only with summed concentrations of low molecular weight PAHs normalized to the SQS and
CSL guidelines.
In contrast, percent urchin fertilization and cytochrome P450 HRGS induction were highly
correlated with many of the chemical groups when normalized to all three sets of guidelines.
Percent urchin fertilization was significantly correlated with all but the trace metals groups at
probability levels 50.0001. Correlations with the concentrations of PAHs were consistent and
highly significant. Correlations with trace metals were weaker. In the cytochrome P450 HRGS
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