Table 4. Quality-assurance tests comparing samples collected using the autosampler with samples collected using depth- and width-integrating techniques, and testing carryover between sequential samples, Fanno and Dairy Creeks, Oregon.
[The cross-section coefficient (or box coefficient) is determined as Ci/Cp, where Cp is the concentration from the pumping sampler and Ci is the integrated, cross sectional concentration, collected according to U.S. Geological Survey sampling protocols. Abbreviations: E. coli, Escherichia coli bacteria; AS, autosampler; Rep, replicate; FC, Fanno Creek near Durham; EWI, equal width increment; DI, distilled, deionized water; DC, Dairy Creek at Highway 8; <, less than; E, estimated; mg/L, milligram per liter; N, nitrogen, P, phosphorus; mL, milliliter]
| Description and time of sample collection |
Test sequence No. |
Location, date |
Total suspended solids (mg/L) |
Ammonium-nitrogen (mg/L as N) |
Total Kjeldahl nitrogen(mg/L as N) |
Nitrate (mg/L as N) |
Total phosphorus (mg/L as P) |
Soluble reactive phosphorus (mg/L as P) |
Chloride (mg/L) |
E. coli
(colonies per 100 mL) |
Comments |
| AS, Native Rep No. 1 11:30 |
1 |
FC, 06-06-2002 |
4 |
0.037 |
0.310 |
0.545 |
0.126 |
0.086 |
13.0 |
270 |
Native |
| AS, Native Rep No. 2 11:35 |
2 |
4 |
0.036 |
0.247 |
0.537 |
0.123 |
0.082 |
13.1 |
390 |
| Median (Cp ) |
|
4 |
0.037 |
0.279 |
0.541 |
0.125 |
0.084 |
13.1 |
330 |
| Standard Deviation |
|
0 |
0.001 |
0.045 |
0.005 |
0.002 |
0.003 |
0.071 |
84.9 |
| EWI, Native Rep No. 1, 11:40 |
4 |
FC, 06-06-2002 |
6 |
0.040 |
0.279 |
0.547 |
0.128 |
0.079 |
13.3 |
190 |
Comparison of autosampler with equal-width-increment sample |
| EWI, Native Rep No. 2, 11:40 |
5 |
1 |
0.041 |
0.311 |
0.544 |
0.131 |
0.086 |
13.3 |
230 |
| EWI, Native Rep No. 3, 11:40 |
6 |
3 |
0.040 |
0.291 |
0.542 |
0.127 |
0.081 |
13.3 |
240 |
| Median (Ci ) |
|
3 |
0.040 |
0.291 |
0.544 |
0.128 |
0.081 |
13.3 |
230 |
| Standard Deviation |
|
2.5 |
0.001 |
0.016 |
0.002 |
0.002 |
0.004 |
0.000 |
26.5 |
| Cross-section coefficient |
|
0.75 |
1.10 |
1.04 |
1.01 |
1.03 |
0.96 |
1.02 |
0.70 |
| AS, DI Blank, after Natives, 11:45 |
7 |
FC, 06-06-2002 |
1 |
<0.01 |
< 0.05 |
0.008 |
< 0.025 |
< 0.005 |
< 0.25 |
< 1 |
Test for carryover |
| AS, Kicked up turbidity, Rep No. 1, 12:00 |
8 |
FC, 06-06-2002 |
76 |
0.035 |
0.474 |
0.544 |
0.204 |
0.084 |
13.2 |
240 |
Tests dilution (from DI blank in sample 7) |
| AS, Kicked up turbidity, Rep No. 2, 12:02 |
9 |
147 |
0.036 |
0.452 |
0.542 |
0.276 |
0.084 |
13.2 |
330 |
| AS, Kicked up turbidity, Rep No. 3, 12:05 |
10 |
28 |
0.035 |
0.287 |
0.539 |
0.152 |
0.085 |
13.1 |
190 |
| Median |
|
76 |
0.035 |
0.452 |
0.542 |
0.204 |
0.084 |
13.2 |
240 |
| Standard Deviation |
|
59.9 |
0.001 |
0.102 |
0.003 |
0.062 |
0.003 |
0.058 |
70.9 |
| AS, Settled turbidity, 12:14 |
11 |
FC, 06-06-2002 |
5 |
0.035 |
0.19 |
0.543 |
0.117 |
0.081 |
13.2 |
260 |
Test for carryover |
| AS, Settled turbidity, 12:15 |
12 |
3 |
0.034 |
0.312 |
0.545 |
0.127 |
0.077 |
13.3 |
250 |
| AS, Settled turbidity, 12:16 |
13 |
5 |
0.035 |
0.268 |
0.542 |
0.125 |
0.081 |
13.5 |
360 |
| Median |
|
5 |
0.035 |
0.268 |
0.543 |
0.125 |
0.081 |
13.3 |
260 |
| Standard Deviation |
|
1.2 |
0.001 |
0.062 |
0.001 |
0.005 |
0.002 |
0.153 |
60.8 |
| AS, Native Water, 11:26 |
14 |
DC, 11-20-2003 |
13.0 |
E 0.018 |
0.478 |
0.700 |
0.144 |
0.052 |
6.42 |
190 |
Calculation of Cp at Dairy Creek |
| EWI, Native Water, 11:30 |
15 |
12.0 |
E 0.017 |
0.501 |
0.702 |
0.151 |
0.055 |
6.43 |
180 |
| Cross-section coefficient |
|
0.92 |
0.94 |
1.05 |
1.00 |
1.05 |
1.06 |
1.00 |
0.95 |
|
First posted June 18, 2010
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U.S. Department of the Interior | U.S. Geological Survey