was within 2-12% of the true value while in Oregon 10 of the 12 non-DDT pesticides 
were within ±35% of the value in the spiked matrix. Accuracy was not as good in 
Washington with 7 of the 12 pesticides within ±35% of the spiked value. Because 
recoveries from a spiked matrix is not as rigorous an evaluation of accuracy as those 
derived from natural matrices, small differences in concentrations should not be over 
interpreted. 
California met the accuracy DQOs for sediment PAHs. In Oregon, the average 
percent deviation from the true value for PAHs was 40% compared to the DQO of 30%. 
Eight of the 20 PAHs measured in the reference material deviated from the true values 
by > 35%, though only benzo(b)fluoranthene and dibenz(a,h)anthracene showed 
deviations > 50%. Washington also failed to meet the overall standard, with an average 
percent deviation for all PAHs of 44%. Nine of the 23 PAHs measured in Washington 
deviated by > 35% from the true value, with 6 of these compounds deviating by > 50% 
(2,3,5-trimethylnaphthalene, 2,6-dimethylnaphthalene, acenaphthylene, 
benzo(k)fluoranthene, dibenz(a,h)anthracene, dibenzothiophene). The PAH data 
should be interpreted with consideration that Oregon and Washington did not achieve 
the average overall DQOs for PAHs and, in particular, data for compounds deviating by 
> 50% should be interpreted cautiously. 
2.5.4 Metals in Tissue 
The recommended MDL (Table A7-2 in U.S. EPA, 2001) in tissue varies by 
metal, ranging from 0.01 pg/g for mercury to 50 pg/g for iron and zinc. All three states 
met the MDL recommendations for metals in tissue with the following exceptions: at 
0.015 pg/g, Oregon’s MDL for mercury was slightly higher than the recommended 
detection of 0.01 pg/g. Both Oregon and Washington exceeded the recommended MDL 
for tin of 0.05 pg/g with detection limits of 0.15 pg/g and 0.2 - 0.22 pg/g respectively. All 
three states met the requirement for precision. Oregon and Washington met the DQO 
that recovery of metals from matrix spikes should be in the range of 50%-120% of the 
spiked concentration. However, California did not conduct any matrix spikes with 
tissues. In terms of accuracy, all three states met the average and individual DQOs, 
though the Washington standard reference material contained only 7 of the 13 metals. 
2.5.5 Organics in Tissue 
The recommended MDLs (Table A7-2 in U.S. EPA, 2001) in tissue are 2.0 ng/g 
for both PCBs and the chlorinated pesticides. All three states met the MDL 
recommendations for organics in tissues with the following exceptions: Oregon had a 
MDL of 20 ng/g for endosulfan I, endosulfan II, and endosulfan sulfate. Oregon had a 
MDL of 200 ng/g for toxaphene while California had a detection limit of 10 ng/g. Oregon 
had a detection limit of 10 ng/g for endrin. All three states met the requirement for 
precision that the average RPD or CV for PCBs and pesticides in replicate samples be 
<30%. Oregon and Washington met the DQO that recovery of PCBs and pesticides 
from matrix spikes should be in the range of 50%-120% of the spiked concentration. 
15 
