Table 7.
Results of Wilcoxon signed-rank test for bias in constituent data for the Quality of Water Service Unit laboratory[Most probable value, Median bias, and Nearest reporting unit reported in same units as Minimum Reporting Limit; mg/L, milligrams per liter; DIS, dissolved; --, acceptable results; WWR, whole-water recoverable; NEG, negative bias; TITR, electrometric titration; POS, positive bias;
mg/L, micrograms per liter; ICP-AES, inductively coupled plasma-atomic emission spectrometry; GF-AAS, graphite furnace-atomic absorption spectrophotometry; IC, ion chromatography; GRAV, gravimetric; ISE, ion-selective electrode; ICP-AES/T, inductively coupled plasma-atomic emission spectrometry, trace; CV-AAS, cold vapor-atomic absorption spectrophotometry; F-AAS, flame-atomic absorption spectrophotometry; LIS, low ionic strength]
Constituent and method of analysis |
Most probable value |
Number of determinations |
Median bias |
Nearest reporting unit |
p-value |
Bias |
NUTRIENT CONSTITUENTS |
||||||
Ammonia as nitrogen (DIS) Minimum Reporting Limit 0.015 mg/L |
||||||
0.062 |
4 |
-0.005 |
0.01 |
0.50000 |
-- |
|
0.155 |
16 |
-0.005 |
0.01 |
0.01440 |
-- |
|
0.266 |
16 |
0.004 |
0.01 |
0.01657 |
-- |
|
Ammonia plus organic nitrogen as nitrogen (DIS) Minimum Reporting Limit 0.2 mg/L |
||||||
0.132 |
4 |
0.07 |
0.1 |
0.12500 |
-- |
|
0.250 |
16 |
0.00 |
0.1 |
0.84619 |
-- |
|
0.474 |
16 |
0.00 |
0.1 |
0.58948 |
-- |
|
2.37 |
5 |
-0.07 |
0.1 |
0.31250 |
-- |
|
Ammonia plus organic nitrogen as nitrogen (WWR) Minimum Reporting Limit 0.2 mg/L |
||||||
0.132 |
11 |
0.07 |
0.1 |
0.00098 |
-- |
|
0.250 |
24 |
0.01 |
0.1 |
0.33103 |
-- |
|
0.474 |
24 |
-0.03 |
0.1 |
0.19438 |
-- |
|
0.480 |
3 |
-0.14 |
0.1 |
0.25000 |
-- |
|
2.37 |
17 |
-0.07 |
0.1 |
0.10536 |
-- |
|
Nitrate plus nitrite as nitrogen (DIS) Minimum Reporting Limit 0.05 mg/L |
||||||
0.073 |
4 |
-0.003 |
0.01 |
0.12500 |
-- |
|
0.182 |
16 |
-0.012 |
0.01 |
0.00003 |
NEG |
|
0.344 |
16 |
-0.004 |
0.01 |
0.13696 |
-- |
|
1.72 |
5 |
-0.020 |
0.01 |
0.75000 |
-- |
|
Orthophosphate as phosphorus (DIS) Minimum Reporting Limit 0.01 mg/L |
||||||
0.152 |
8 |
0.008 |
0.01 |
0.29688 |
-- |
|
0.232 |
8 |
-0.002 |
0.01 |
0.80469 |
-- |
|
Phosphorus as phosphorus (DIS) Minimum Reporting Limit 0.02 mg/L |
||||||
0.050 |
4 |
0.010 |
0.01 |
0.25000 |
-- |
|
0.167 |
16 |
-0.017 |
0.01 |
0.00006 |
NEG |
|
Phosphorus as phosphorus (WWR) Minimum Reporting Limit 0.01 mg/L |
||||||
0.050 |
11 |
0.010 |
0.01 |
0.12500 |
-- |
|
0.167 |
24 |
-0.022 |
0.01 |
0.00000 |
NEG |
|
0.223 |
3 |
-0.003 |
0.01 |
0.25000 |
-- |
|
INORGANIC CONSTITUENTS |
||||||
Alkalinity (WWR,TITR) Minimum Reporting Limit 1 mg/L |
||||||
68.5 |
8 |
-3.0 |
1 |
0.00781 |
NEG |
|
76.0 |
12 |
2.0 |
1 |
0.00049 |
POS |
|
78.5 |
8 |
2.1 |
1 |
0.00781 |
POS |
|
106 |
11 |
-1.0 |
1 |
0.08594 |
-- |
|
107 |
11 |
2.6 |
1 |
0.00098 |
POS |
|
130 |
8 |
1.8 |
1 |
0.06250 |
-- |
|
Aluminum (DIS, ICP-AES) Minimum Reporting Limit 3 mg/L |
||||||
20.5 |
8 |
-1.0 |
1 |
0.03906 |
-- |
|
35.7 |
8 |
0.4 |
1 |
0.43750 |
-- |
|
53.0 |
7 |
0.1 |
1 |
0.57813 |
-- |
|
Aluminum (WWR, ICP-AES) Minimum Reporting Limit 3 mg/L |
||||||
20.5 |
8 |
3.5 |
1 |
0.00781 |
POS |
|
35.7 |
8 |
4.9 |
1 |
0.00781 |
POS |
|
53.0 |
6 |
3.6 |
1 |
0.03125 |
POS |
|
Arsenic (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
2.78 |
3 |
0.0 |
1 |
1.00000 |
-- |
|
4.05 |
8 |
-0.9 |
1 |
0.01563 |
-- |
|
5.00 |
3 |
-0.6 |
1 |
0.25000 |
-- |
|
5.30 |
6 |
-0.6 |
1 |
0.06250 |
-- |
|
6.04 |
6 |
-0.7 |
1 |
0.15625 |
-- |
|
7.50 |
4 |
-0.2 |
1 |
0.37500 |
-- |
|
Barium (DIS, GF-AAS) Minimum Reporting Limit 5 mg/L |
||||||
11.0 |
4 |
0.0 |
1 |
0.00000 |
-- |
|
38.5 |
6 |
0.0 |
1 |
1.00000 |
-- |
|
55.9 |
5 |
-0.9 |
1 |
0.37500 |
-- |
|
Barium (DIS, ICP-AES) Minimum Reporting Limit 0.2 mg/L |
||||||
11.0 |
4 |
0.0 |
1 |
1.00000 |
-- |
|
55.9 |
3 |
-0.9 |
1 |
0.50000 |
-- |
|
Barium (WWR, ICP-AES) Minimum Reporting Limit 0.2 mg/L |
||||||
38.5 |
8 |
-1.5 |
1 |
0.00781 |
NEG |
|
55.9 |
8 |
-2.9 |
1 |
0.00781 |
NEG |
|
67.1 |
8 |
-3.1 |
1 |
0.00781 |
NEG |
|
Cadmium (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
3.75 |
3 |
-0.2 |
1 |
0.75000 |
-- |
|
7.50 |
8 |
0.0 |
1 |
0.96875 |
-- |
|
7.68 |
7 |
-0.1 |
1 |
0.93750 |
-- |
|
25.3 |
3 |
-0.3 |
1 |
1.00000 |
-- |
|
28.7 |
8 |
-1.7 |
1 |
0.00781 |
NEG |
|
37.9 |
4 |
-0.9 |
1 |
0.62500 |
-- |
|
Calcium (DIS, ICP-AES) Minimum Reporting Limit 0.02 mg/L |
||||||
12.6 |
7 |
0.4 |
1 |
0.01563 |
-- |
|
25.4 |
8 |
-0.4 |
1 |
0.18750 |
-- |
|
30.4 |
7 |
-0.4 |
1 |
0.48438 |
-- |
|
31.4 |
12 |
-0.4 |
1 |
0.01123 |
-- |
|
34.7 |
6 |
0.8 |
1 |
0.68750 |
-- |
|
40.9 |
8 |
-0.9 |
1 |
0.25781 |
-- |
|
42.0 |
11 |
-1.0 |
1 |
0.18750 |
-- |
|
53.3 |
11 |
-0.3 |
1 |
0.19629 |
-- |
|
58.1 |
8 |
-0.1 |
1 |
0.80469 |
-- |
|
Chloride (DIS, IC) Minimum Reporting Limit 0.1 mg/L |
||||||
5.35 |
8 |
0.35 |
0.1 |
0.01563 |
POS |
|
30.1 |
8 |
1.0 |
1 |
0.00781 |
-- |
|
38.6 |
8 |
1.5 |
1 |
0.00781 |
POS |
|
46.0 |
12 |
1.0 |
1 |
0.00049 |
-- |
|
48.8 |
3 |
0.3 |
1 |
0.25000 |
-- |
|
56.7 |
11 |
2.3 |
1 |
0.00098 |
POS |
|
60.4 |
8 |
1.7 |
1 |
0.00781 |
POS |
|
69.0 |
8 |
2.0 |
1 |
0.00781 |
POS |
|
78.5 |
11 |
2.5 |
1 |
0.00098 |
POS |
|
85.3 |
8 |
1.8 |
1 |
0.00781 |
POS |
|
Chromium (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
1.94 |
8 |
-0.1 |
1 |
0.25000 |
-- |
|
11.6 |
8 |
-0.6 |
1 |
0.01563 |
-- |
|
43.4 |
8 |
-1.4 |
1 |
0.00781 |
NEG |
|
Chromium (WWR, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
3.88 |
6 |
-0.7 |
1 |
0.03125 |
-- |
|
39.5 |
8 |
-1.5 |
1 |
0.03125 |
NEG |
|
59.3 |
10 |
-1.3 |
1 |
0.09570 |
-- |
|
Copper (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
3.25 |
8 |
0.2 |
1 |
0.57813 |
-- |
|
15.5 |
8 |
0.5 |
1 |
0.28906 |
-- |
|
37.5 |
8 |
1.5 |
1 |
0.00781 |
POS |
|
Copper (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
6.50 |
3 |
-0.4 |
1 |
0.50000 |
-- |
|
31.0 |
3 |
-1.0 |
1 |
0.50000 |
-- |
|
46.5 |
4 |
0.5 |
1 |
1.00000 |
-- |
|
Copper (WWR, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
15.5 |
8 |
-0.5 |
1 |
0.07031 |
-- |
|
37.5 |
8 |
0.5 |
1 |
0.63281 |
-- |
|
47.0 |
8 |
0.0 |
1 |
0.09375 |
-- |
|
Dissolved Solids (DIS, GRAV) Minimum Reporting Limit 1 mg/L |
||||||
219 |
8 |
2.8 |
1 |
0.06250 |
-- |
|
284 |
12 |
9.0 |
1 |
0.00098 |
POS |
|
324 |
8 |
7.5 |
1 |
0.05469 |
-- |
|
384 |
11 |
10.0 |
1 |
0.00098 |
POS |
|
469 |
11 |
7.0 |
1 |
0.02148 |
POS |
|
519 |
8 |
13.5 |
1 |
0.01563 |
POS |
|
Fluoride (DIS, ISE) Minimum Reporting Limit 0.1 mg/L |
||||||
0.308 |
8 |
-0.01 |
0.1 |
0.00781 |
-- |
|
0.421 |
3 |
0.08 |
0.1 |
0.25000 |
-- |
|
0.520 |
20 |
-0.02 |
0.1 |
0.21825 |
-- |
|
0.780 |
8 |
0.02 |
0.1 |
0.00781 |
-- |
|
0.800 |
11 |
0.00 |
0.1 |
0.00000 |
-- |
|
0.855 |
8 |
0.05 |
0.1 |
0.79688 |
-- |
|
0.920 |
8 |
-0.02 |
0.1 |
0.00781 |
-- |
|
1.04 |
8 |
-0.04 |
0.1 |
0.00781 |
-- |
|
1.14 |
11 |
-0.04 |
0.1 |
0.82813 |
-- |
|
Iron (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
1.88 |
8 |
1.1 |
1 |
0.00781 |
POS |
|
3.75 |
6 |
0.3 |
1 |
0.03125 |
-- |
|
5.90 |
8 |
-1.9 |
1 |
0.00781 |
NEG |
|
6.70 |
5 |
-1.7 |
1 |
0.06250 |
-- |
|
37.7 |
6 |
2.4 |
1 |
1.00000 |
-- |
|
114 |
8 |
-4 |
10 |
0.00781 |
-- |
|
118 |
8 |
-8 |
10 |
0.01563 |
-- |
|
150 |
6 |
1 |
10 |
0.81250 |
-- |
|
171 |
10 |
-1 |
10 |
0.07422 |
-- |
|
Iron (WWR, ICP-AES) Minimum Reporting Limit 3 mg/L |
||||||
6.70 |
6 |
1.8 |
1 |
0.03125 |
POS |
|
37.7 |
3 |
1.4 |
1 |
0.25000 |
-- |
|
150 |
4 |
1 |
10 |
1.00000 |
-- |
|
Iron (WWR, ICP-AES/T) Minimum Reporting Limit 1 mg/L |
||||||
37.7 |
3 |
1.4 |
1 |
0.25000 |
-- |
|
150 |
4 |
1 |
10 |
0.12500 |
-- |
|
Lead (DIS, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
2.24 |
6 |
-0.2 |
1 |
0.03125 |
-- |
|
51.5 |
8 |
-1.5 |
1 |
0.39063 |
-- |
|
77.3 |
10 |
0.3 |
1 |
0.74805 |
-- |
|
Lead (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
2.24 |
3 |
0.8 |
1 |
0.25000 |
-- |
|
4.78 |
7 |
0.2 |
1 |
0.01563 |
-- |
|
6.00 |
7 |
0.0 |
1 |
0.50000 |
-- |
|
51.5 |
3 |
-4.5 |
1 |
0.25000 |
-- |
|
54.7 |
8 |
-1.2 |
1 |
0.31250 |
-- |
|
77.3 |
4 |
-0.8 |
1 |
0.87500 |
-- |
|
Magnesium (DIS, ICP-AES) Minimum Reporting Limit 0.01 mg/L |
||||||
2.50 |
7 |
0.00 |
0.1 |
1.00000 |
-- |
|
6.00 |
7 |
0.10 |
0.1 |
0.25000 |
-- |
|
6.55 |
8 |
-0.15 |
0.1 |
0.12500 |
-- |
|
7.65 |
12 |
-0.20 |
0.1 |
0.00195 |
NEG |
|
7.74 |
6 |
0.01 |
0.1 |
0.78125 |
-- |
|
9.12 |
8 |
-0.27 |
0.1 |
0.00781 |
NEG |
|
10.6 |
11 |
-0.6 |
1 |
0.00195 |
-- |
|
12.5 |
11 |
-0.5 |
1 |
0.00391 |
-- |
|
13.9 |
8 |
0.1 |
1 |
0.64844 |
-- |
|
Manganese (DIS, ICP-AES) Minimum Reporting Limit 0.2 mg/L |
||||||
1.20 |
6 |
0.05 |
0.1 |
0.25000 |
-- |
|
6.80 |
5 |
0.00 |
0.1 |
0.50000 |
-- |
|
59.0 |
6 |
0.5 |
1 |
0.25000 |
-- |
|
212 |
8 |
-2 |
10 |
0.64844 |
-- |
|
261 |
8 |
-1 |
10 |
0.00781 |
-- |
|
317 |
10 |
3 |
10 |
0.05859 |
-- |
|
Manganese (WWR, ICP-AES) Minimum Reporting Limit 0.2 mg/L |
||||||
1.20 |
3 |
0.00 |
0.1 |
1.00000 |
-- |
|
6.80 |
7 |
-0.10 |
0.1 |
0.03125 |
-- |
|
59.0 |
6 |
-1.5 |
1 |
0.06250 |
-- |
|
212 |
3 |
-2 |
10 |
0.25000 |
-- |
|
261 |
8 |
-11 |
10 |
0.00781 |
NEG |
|
317 |
4 |
-7 |
10 |
0.25000 |
-- |
|
Mercury (WWR, CV-AAS) Minimum Reporting Limit 0.1 mg/L |
||||||
0.53 |
3 |
-0.03 |
0.1 |
0.25000 |
-- |
|
0.76 |
12 |
-0.01 |
0.1 |
0.35742 |
-- |
|
0.93 |
8 |
0.02 |
0.1 |
1.00000 |
-- |
|
2.27 |
10 |
0.03 |
0.1 |
0.82617 |
-- |
|
Nickel (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
3.28 |
8 |
0.13 |
0.1 |
0.35938 |
-- |
|
15.1 |
8 |
-0.1 |
1 |
0.64844 |
-- |
|
39.4 |
8 |
-0.4 |
1 |
0.00781 |
-- |
|
Nickel (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
6.55 |
3 |
-0.5 |
1 |
0.25000 |
-- |
|
32.8 |
3 |
-1.8 |
1 |
0.50000 |
-- |
|
49.2 |
4 |
-3.2 |
1 |
0.12500 |
-- |
|
Nickel (WWR, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
15.1 |
8 |
-1.1 |
1 |
0.28906 |
-- |
|
39.4 |
8 |
-2.4 |
1 |
0.00781 |
NEG |
|
53.0 |
8 |
-2.5 |
1 |
0.00781 |
NEG |
|
Potassium (DIS, F-AAS) Minimum Reporting Limit 0.1 mg/L |
||||||
0.68 |
7 |
-0.08 |
0.1 |
0.18750 |
-- |
|
1.85 |
8 |
-0.10 |
0.1 |
0.14844 |
-- |
|
2.20 |
8 |
-0.10 |
0.1 |
0.03125 |
-- |
|
2.53 |
6 |
-0.03 |
0.1 |
0.25000 |
-- |
|
2.75 |
8 |
-0.05 |
0.1 |
0.17188 |
-- |
|
3.27 |
12 |
-0.07 |
0.1 |
0.36963 |
-- |
|
4.47 |
11 |
-0.07 |
0.1 |
0.20703 |
-- |
|
4.77 |
11 |
-0.17 |
0.1 |
0.16211 |
-- |
|
5.50 |
8 |
-0.10 |
0.1 |
0.44531 |
-- |
|
Selenium (WWR, GF-AAS) Minimum Reporting Limit 1 mg/L |
||||||
2.42 |
3 |
0.49 |
0.1 |
0.25000 |
-- |
|
5.00 |
3 |
0.70 |
0.1 |
0.50000 |
-- |
|
7.50 |
3 |
0.40 |
0.1 |
0.50000 |
-- |
|
Silica (DIS, ICP-AES) Minimum Reporting Limit 0.01 mg/L |
||||||
3.90 |
8 |
-0.10 |
0.1 |
0.03125 |
-- |
|
6.50 |
12 |
-0.20 |
0.1 |
0.00049 |
NEG |
|
7.52 |
8 |
0.04 |
0.1 |
1.00000 |
-- |
|
9.17 |
11 |
-0.17 |
0.1 |
0.00098 |
NEG |
|
11.1 |
8 |
-0.1 |
1 |
0.00781 |
-- |
|
1 11.1 |
11 |
-0.1 |
1 |
0.03711 |
-- |
|
Silver (DIS, GF-AAS, LIS) Minimum Reporting Limit 0.2 mg/L |
||||||
0.57 |
3 |
0.435 |
0.01 |
0.25000 |
-- |
|
4.09 |
6 |
-0.19 |
0.1 |
0.12500 |
-- |
|
6.04 |
5 |
0.27 |
0.1 |
0.62500 |
-- |
|
Silver (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
0.57 |
3 |
0.4 |
1 |
0.25000 |
-- |
|
Silver (WWR, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
4.09 |
6 |
-0.3 |
1 |
0.09375 |
-- |
|
6.04 |
4 |
0.1 |
1 |
0.75000 |
-- |
|
7.43 |
4 |
0.0 |
1 |
0.75000 |
-- |
|
Silver (WWR, ICP-AES/T) Minimum Reporting Limit 1 mg/L |
||||||
6.04 |
4 |
-0.1 |
1 |
0.37500 |
-- |
|
7.43 |
4 |
0.0 |
1 |
0.87500 |
-- |
|
Sodium (AA) Minimum Reporting Limit 0.1 mg/L |
||||||
22.7 |
7 |
-0.7 |
1 |
0.46875 |
-- |
|
38.8 |
8 |
-0.3 |
1 |
0.37500 |
-- |
|
54.0 |
12 |
-1.5 |
1 |
0.02148 |
NEG |
|
54.3 |
8 |
-1.3 |
1 |
0.00781 |
NEG |
|
60.9 |
8 |
-1.9 |
1 |
0.01563 |
NEG |
|
62.0 |
6 |
-3.5 |
1 |
0.06250 |
-- |
|
71.9 |
11 |
-0.9 |
1 |
0.17480 |
-- |
|
84.4 |
11 |
-2.4 |
1 |
0.00098 |
NEG |
|
96.2 |
8 |
-4.7 |
1 |
0.00781 |
NEG |
|
Strontium (DIS, ICP-AES) Minimum Reporting Limit 0.5 mg/L |
||||||
197 |
7 |
3 |
10 |
0.68750 |
-- |
|
270 |
8 |
-10 |
10 |
0.25781 |
-- |
|
498 |
8 |
-18 |
10 |
0.00781 |
NEG |
|
Strontium (DIS, ICP-AES/T) Minimum Reporting Limit 0.5 mg/L |
||||||
23.0 |
8 |
0.0 |
1 |
0.50000 |
-- |
|
34.5 |
8 |
0.5 |
1 |
0.26563 |
-- |
|
201 |
6 |
-0.5 |
10 |
0.37500 |
-- |
|
Strontium (WWR, ICP-AES) Minimum Reporting Limit 0.5 mg/L |
||||||
92.0 |
4 |
-2.0 |
1 |
0.12500 |
-- |
|
224 |
4 |
-4 |
10 |
0.12500 |
-- |
|
279 |
6 |
-9 |
10 |
0.03125 |
-- |
|
Strontium (WWR, ICP-AES/T) Minimum Reporting Limit 0.5 mg/L |
||||||
92.0 |
4 |
-3.0 |
1 |
0.12500 |
-- |
|
224 |
4 |
-4 |
10 |
0.12500 |
-- |
|
Sulfate (DIS, IC) Minimum Reporting Limit 0.2 mg/L |
||||||
14.5 |
8 |
-0.5 |
1 |
0.00781 |
-- |
|
58.5 |
8 |
0.5 |
1 |
0.00781 |
-- |
|
58.5 |
3 |
1.5 |
1 |
0.25000 |
-- |
|
59.0 |
8 |
1.0 |
1 |
0.01563 |
-- |
|
69.0 |
8 |
1.5 |
1 |
0.03906 |
POS |
|
75.0 |
12 |
1.0 |
1 |
0.00098 |
-- |
|
104 |
11 |
6 |
10 |
0.00391 |
-- |
|
113 |
8 |
-3 |
10 |
0.64844 |
-- |
|
114 |
11 |
6 |
10 |
0.00098 |
-- |
|
132 |
8 |
-2 |
10 |
0.64844 |
-- |
|
Zinc (DIS, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
5.46 |
8 |
0.0 |
1 |
1.00000 |
-- |
|
29.6 |
8 |
5.9 |
1 |
0.00781 |
POS |
|
115 |
8 |
6 |
10 |
0.00781 |
-- |
|
Zinc (WWR, ICP-AES) Minimum Reporting Limit 1 mg/L |
||||||
10.0 |
3 |
-0.5 |
1 |
0.25000 |
-- |
|
30.0 |
3 |
0.0 |
1 |
1.00000 |
-- |
|
38.5 |
4 |
-0.0 |
1 |
1.00000 |
-- |
|
48.9 |
8 |
0.7 |
1 |
0.37500 |
-- |
|
62.8 |
7 |
-0.8 |
1 |
0.31250 |
-- |
|
134 |
8 |
6 |
10 |
0.03125 |
-- |