sources (i.e., red alder in the watershed and oceanic input) rather than anthropogenic sources. Systems 
in the PNW appear to have relatively high background levels of DIN and DIP compared to other 
estuaries in the U.S. (U.S. EPA, 2004a). 
Table 6.3 Percentiles for DIN (pM) calculated using Yaquina (1998-2006), Classification 
(2004-2005), and NCA Oregon estuaries (1999-2000) data sets. NCA and Classification 
values are for dry season only, while Yaquina data include values for dry and wet seasons. 
Percentiles for DIN (pM) 
Data set 
25 lh 
50 th 
75 th 
Sample Size 
Zone 1 
Yaquina 
Dry 
8.3 
14.1 
20.4 
1113 
Wet 
6.8 
11.6 
19.1 
520 
Classification 
5.7 
11.1 
18.6 
68 
NCA 
6.0 
8.6 
11.8 
36 
NCA excluding Columbia 
5.8 
8.4 
11.8 
33 
Zone 2 
Yaquina 
Dry 
7.3 
13.7 
23.1 
915 
Wet 
30.7 
55.2 
73.5 
354 
Classification 
8.3 
14.0 
36.9 
88 
NCA 
7.0 
9.4 
13.2 
89 
NCA excluding Columbia 
4.8 
7.2 
11.9 
27 
Table 6.4 Percentiles for PO 4 (pM) using Yaquina (1998-2006), Classification (2004-2005), 
and NCA Oregon estuaries (1999-2000) data sets. NCA and Classification values are for dry 
season only, while Yaquina 
include dry and wet season values. 
3- 
Percentiles for PCC fuM) 
• 
Data set 
Sample Size 
25th 
50 lh 
75 lh 
Zone 1 
Yaquina 
Dry 
0.88 
1.25 
1.69 
1114 
Wet 
0.39 
0.59 
0.77 
519 
Classification 
0.62 
0.89 
1.20 
68 
NCA 
0.76 
0.95 
1.15 
36 
NCA excluding Columbia 
0.76 
1.00 
1.16 
33 
Zone 2 
Yaquina 
Dry 
0.43 
0.64 
0.99 
915 
Wet 
0.41 
0.49 
0.62 
354 
Classification 
0.33 
0.45 
0.75 
88 
NCA 
0.35 
0.52 
0.71 
89 
NCA excluding Columbia 
0.18 
0.33 
0.73 
27 
i r 
49 
