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

As a corollary to and verification of the cytochrome P450 HRGS toxicity tests results, Columbia
Analytical Services performed further chemical testing on a select number of the central Puget
Sound samples (Jack Anderson, CAS, personal communication). Ten of the samples were
selected for cytochrome P450 HRGS analyses at two time periods, exposures of 6 hours and 16
hours. Experimentation with this assay has revealed that the RGS response is optimal at 6 hours
of exposure when tests are done with PAHs, whereas the response is optimal at 16 hours when
tests are done with dioxins. All ten samples selected for these two time series tests (stations 182,
184, 193, 198-204) were collected in Elliott Bay or the lower Duwamish River. In all the
samples except 184, the response was stronger at 6 hours than at 16 hours, indicating the
presence of PAHs in the extracts. hi most cases, the ratios between the two responses were
factors of about five-fold.
Five of the samples (from stations 184, 193, 199,200, and 204) were selected for chemical
analyses for PAHs and PCBs. The correlation between total PAH concentrations in the extracts
of five samples and RGS responses was significant (R? = 0.75). Total PAH concentrations (sums
of 27 parent compounds) equaled 240 to 5975 ppb.
In the sample from station 184, the responses at the two time periods were equivalent, suggesting
that both chlorinated organics and PAHs were present. However, chemical analyses of the
extracts for the five samples indicated that the sums of PCB congeners were very low: 0 to 14
ppb. The highest concentration of PAHs (5975 ppb) was found in sample 184 and the total PCB
concentration was 0, contradictory to what was expected. The data suggest that chlorinated
organics other than planar PCB congeners may have occurred in sample 184.
Spatial Patterns and Gradients in Toxicity
Spatial patterns (or gradients) in toxicity were illustrated in three sets of figures, including maps
for the amphipod and urchin test results (Figures 4-8), MicrotoxTM results (Figures 9-13), and
cytochrome P450 HRGS test results (Figures 14- 18). Amphipod and urchin test results are
displayed as symbols keyed to the statistical significance of the responses. Stations are shown in
which amphipod survival was not significantly different from CLIS controls (~20.05, (i.e.,nontoxic)),
was significantly different from controls (p