3.2.4 Sediment Contaminants 
To assess the degree of sediment contamination in West Coast estuaries, the 
sediment concentrations of contaminants were compared with both the ERM and ERL 
guidelines (Long et al., 1995). A total of 28 compounds or groups of compounds were 
included on the list of contaminants used by the NCCR II report (U.S. EPA 2004). The 
analysis of the 2002 intertidal data for West Coast estuaries excluded nickel and two 
PAHs, phenanthrene and dibenzothiophene. Phenanthrene and dibenzothiophene 
were excluded because values were not available from all three states. Nickel was 
excluded because the ERM value has a low reliability for West Coast conditions where 
high natural crustal concentrations of nickel exist (Long et al., 1995; Long et al., 2000; 
Lauenstein et al., 2000). 
Sediment Contaminant Guidelines (Long et al., 1995) 
ERM (Effects Range Median)—Determined for each chemical as the 50th percentile (median) 
in a database of ascending concentrations associated with adverse biological effects. 
ERL (Effects Range Low)—Determined values for each chemical as the 10th percentile in a 
database of ascending concentrations associated with adverse biological effects. 
Sediment concentrations exceeded their respective ERM values at only five 
stations, representing 0.3% of the intertidal estuarine area of the West Coast (Appendix 
Table 3). Four sites were located in Southern California (none in San Francisco Bay), 
one in Oregon, and none in Washington. In all cases, the exceedances of the ERMs 
were due to DDT and/or its congener 4,4’ DDE. Three of the four California sites were 
in Point Mugu Lagoon, and the remaining site was in Newport Harbor. 
Any site that had five or more compounds that exceeded their ERL values was 
classified as having fair condition in the NCCR II report (U.S. EPA 2004). As with the 
ERMs, nickel was excluded from the analysis. To ensure that the analysis was not 
biased by PAHs, only one exceedance was counted if a site exceeded the ERL for 
LMW PAHs, HMW PAHs, or total PAHs. A total of 14 stations had five or more 
pollutants exceeding the ERL value, of which 3 also exceeded one or more ERMs 
(Appendix Table 3). The 14 sites represent only 0.21% of the intertidal area of the West 
Coast estuaries. All of these sites occurred in California, with 5 sites located in either 
high or low marsh within the San Francisco Bay, while the remaining 9 sites were in 
Southern California. Two additional sites, one in California and one in Oregon, had 
sediments pollutants that exceeded one or more ERMs, but had less than five pollutants 
exceeding the ERL (Appendix Table 3). 
Another indicator approach to evaluation of the level of potential problems 
resulting from sediment contamination is the use of the Effects Range Median Quotient 
(ERM-Q, Long and MacDonald, 1998). 
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