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

Human Reporter Gene System (Cytochrome P450) Response - Organic
Solvent Extract
This test is intended to identify samples in which there are elevated concentrations of mixed-
function oxygenase-inducing organic compounds, notably the dioxins and higher molecular
weight PAHs. It is performed with a cultured cell line that provides very reliable and consistent
results. Tests are conducted with an organic solvent extract to ensure that potentially toxic
organic compounds are eluted. High cytochrome P450 HRGS induction may signify the
presence of substances that could cause or contribute to the induction of mutagenic andlor
carcinogenic responses in local resident biota (Anderson et al., 1995, 1996).
In central Puget Sound, the cytochrome P450 HRGS assay indicated that samples in which
results exceeded 1 1.1 and 37.1 pglg B(a)P equivalents represented approximately 32.3% and
3.2%, respectively, of the total survey area. In contrast, the equivalent estimates for northern
Puget Sound were 2.6% and 0.03% of the study area (Long et al., 1999a). Relatively high
responses were recorded in many samples from large strata sampled in central Puget Sound,
thereby resulting in larger estimated areas. hi northern Puget Sound the samples with elevated
responses were collected primarily in the small strata in Everett Harbor.
These tests were performed in NOAA surveys in 8 estuaries where estimates of spatial extent
could be made: northern and central Puget Sound (WA), northern Chesapeake Bay (MD), Sabine
Lake (TX), Biscayne Bay (FL), Delaware Bay (DE), Galveston Bay (TX), and a collection of
Southern California coastal estuaries (CA). Based upon the critical values of 1 1.1 and 37. lpglg,
the samples from central Puget Sound ranked third highest among the 8 study areas for which
there are equivalent data (Table 39). Toxic responses greater than 11.1 pglg were most
widespread in samples from northern Chesapeake Bay and Southern California estuaries. Toxic
responses greater than 37.1 pglg were most widespread in northern Chesapeake Bay followed by
Delaware Bay and central Puget Sound. In the central Puget Sound area, RGS responses greater
than 1 1.1 pglg were more widespread than in the combined national average (20%), whereas
responses greater than 37.1 pglg were less widespread than the national average of 9.2%.
In central Puget Sound, RGS assay responses ranged from 0.4 pglg to 223 pglg and there were 27
samples in which the responses exceeded 37.1 pglg. In northern Puget Sound, responses ranged
from 0.3 pglg to 104.6 pglg and only four samples had responses greater than 37.1 pglg. In
analyses of 30 samples from Charleston Harbor and vicinity, results ranged from 1.8 pglg to 86.3
pglg and there were nine samples with results greater than 37.1 pglg. In the 12 1 samples from
Biscayne Bay, results ranged from 0.4 to 37.0 pglg B[a]P equivalents. Induction responses in 30
samples from San Diego Bay were considerably higher than those from all other areas. Assay
results ranged from 5 pglg to 1 10 pglg B[a]P equivalents and results from 18 samples exceeded
37.1 pglg in San Diego Bay. Responses in eight samples exceeded 80 pglg.
The percentages of samples from different survey areas with cytochrome P450 HRGS responses
greater than 37.1 pglg were: 60% in San Diego Bay, 30% in Charleston Harbor, 27% in central
Puget Sound, 23% in Delaware Bay, 11% in Sabine Lake, 4% in northern Puget Sound, 1% in
Galveston Bay, and 0% in both Biscayne Bay and Southern California estuaries. Based upon
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