Table 6. Summary of water-quality data for ground-water samples collected from wells completed in coalbed aquifers
[MRL, minimum reporting level; °C, degrees Celsius; NA, not applicable; µS/cm, microsiemens per centimeter; mg/L, milligrams per liter; CaCO3, calcium carbonate; NC, not calculated because percentile is less than highest minimum reporting level]
|
Characteristic or constituent |
Number of detections/number of samples |
Highest MRL |
Minimum |
10th percentile |
25th percentile |
50th percentile (Median) |
75th percentile |
90th percentile |
Maximum |
|---|---|---|---|---|---|---|---|---|---|
|
Physical characteristics |
|||||||||
|
Water temperature, field measurement (°C) |
13/13 |
NA |
14 |
15.2 |
17 |
19 |
20 |
26.6 |
27 |
|
pH, field measurement (standard units) |
13/13 |
0.1 |
6.9 |
6.9 |
7.1 |
7.2 |
7.4 |
7.6 |
7.8 |
|
General mineral characteristics |
|||||||||
|
Acid-neutralizing capacity (ANC), laboratory (mg/L as CaCO3) |
13/13 |
1.0 |
346 |
349.6 |
432 |
584 |
788 |
1,924 |
2,570 |
|
Specific conductance, field measurement (µS/cm at 25°C) |
13/13 |
1.0 |
665 |
672.6 |
839 |
1,070 |
1,610 |
3,504 |
4,180 |
|
Dissolved solids, calculated sum (mg/L) |
13/13 |
NA |
382 |
387.2 |
483 |
644 |
959 |
2,296 |
2,720 |
|
Hardness, total (mg/L as CaCO3) |
13/13 |
NA |
74 |
75.2 |
100 |
150 |
245 |
446 |
550 |
|
Sodium-adsorption ratio (SAR) |
13/13 |
NA |
5 |
5.4 |
6 |
7 |
8 |
19 |
26 |
|
Major ions, in milligrams per liter, dissolved (sample filtered through 0.45-micrometer disposable cartridge filter) |
|||||||||
|
Calcium |
13/13 |
0.02 |
15 |
15.8 |
20 |
36 |
50 |
59 |
62 |
|
Magnesium |
13/13 |
0.01 |
8.4 |
8.5 |
11.4 |
15 |
28 |
37 |
39 |
|
Sodium |
13/13 |
0.09 |
120 |
124 |
160 |
210 |
300 |
736 |
1,000 |
|
Potassium |
13/13 |
0.24 |
4.9 |
5.2 |
7.3 |
12 |
13 |
35 |
48 |
|
Bicarbonate, calculated from ANC1 |
13/13 |
NA |
422 |
426 |
527 |
712 |
1,103 |
2,350 |
3,134 |
|
Chloride |
13/13 |
0.29 |
6.9 |
6.9 |
8 |
9.1 |
14 |
23 |
24 |
|
Sulfate |
5/13 |
0.3 |
< 0.3 |
NC |
NC |
NC |
0.95 |
1.6 |
1.8 |
|
Fluoride |
13/13 |
0.1 |
0.6 |
0.68 |
1.0 |
1.2 |
1.4 |
1.8 |
1.9 |
|
Silica |
3/13 |
0.1 |
7.4 |
8.1 |
9.8 |
10 |
11 |
16 |
20 |
1Equivalent bicarbonate concentrations calculated from acid-neutralizing capacity (ANC) concentrations by dividing ANC concentrations (expressed as milligrams per liter of calcium carbonate) by 0.8202 (Hem, 1985, p. 57).
