CINMS (Fig. 3.3.9). 
Chromium ERL exceedances were much more widespread, with 
sediments exceeding the ERL value at sites along all three states (Fig. 3.3.10). 
Oregon had the highest incidence: 30 of 50 stations, representing 60% of the 
total survey area (Tables 3.3.3, 3.3.4). The highest concentration (296.5 pg/g) 
and highest mean concentration (129.5 pg/g) also occurred off Oregon (Table 
3.3.1). Chromium is naturally present in soils in the Pacific Northwest Coast 
range. Chromium was originally mined from black sand deposits along the 
Oregon coast in Coos County, and a low-grade ore was mined in the 1940’s to 
1950’s in Oregon and northern California, and to a lesser extent in Washington, 
under a federal stockpiling program (Baber et al. 1959). A report by EPA Region 
X on the ecological condition of the estuaries of Oregon and Washington (Hayslip 
et al. 2006) actually excluded chromium, as well as nickel and copper, from its 
aggregate sediment contamination indicator. Chromium was excluded in that 
report because the natural concentration of this metal in the earth’s crust and 
marine shales (100 and 90 pg/g, respectively; Krauskopf and Bird 1995) is 
greater than the ERL (81 pg/g). 
With a few exceptions, sediments within West Coast National Marine 
Sanctuaries (NMSs) were relatively uncontaminated (Tables 3.3.1, 3.3.3, 3.3.4; 
Fig. 3.3.5). The OCNMS had no chemicals in excess of ERM values and only 
two chemicals, chromium and silver, were found in excess of the lower-threshold 
ERL values (Table 3.3.2). There were only four of 30 stations in the OCNMS 
with such chromium exceedances, compared to 31 of 70 stations in nearby non¬ 
sanctuary waters off the coast of Washington and Oregon. Similarly, CINMS had 
no chemicals in excess of ERM values. Three metals (As, Cd, Cr), 2- 
methylnaphthalene, low molecular weight PAHs, total DDT, and 4,4'-DDE were 
found at moderate concentrations, between corresponding ERL and ERM values, 
at multiple sites within the CINMS. Flowever, total DDT, 4,4'-DDE, and chromium 
ERL exceedances were notably less prevalent at CINMS than in non-sanctuary 
waters of California (Figs. 3.3.6, 3.3.7, 3.3.10). DDT and its metabolites are well 
known legacy pesticides in the SCB, and the distributions seen in this survey 
reflect patterns seen in previous years (Schiff 2000, Schiff et al. 2006). In 
contrast, 2-methylnaphthalene contamination, albeit at moderately low levels 
(between ERL and ERM values), was much more prevalent in sediments at the 
CINMS compared to non-sanctuary waters off the coast of California. For 
example, the ERL value was exceeded at 19 of the 27 CINMS stations, 
compared to only 3 of 103 stations in non-sanctuary waters (Table 3.3.4, Fig. 
3.3.9). Schiff et al. (2006) attribute such elevated levels of PAHs in the California 
region to proximity of oil production platforms and reduced degradation of the 
compounds under cold water conditions. However, this does not explain the 
higher incidence of 2-methylnaphthalene contamination specifically around 
CINMS relative to neighboring non-sanctuary waters in the region. 
63 
