Table 2.
Baseline quality of the source well water in 20 select small water systems from the USEPA’s Arsenic Demonstration. These illustrative results reflect a specific sampling date prior to the Arsenic Demo, as listed below.
| AL | BW | BC | GF | LD | DM | FC | CM | LW | PW | SF | ST | SV | WA | WL | WV | CL | DV | SA | SC | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Date (MM/YY) | 2/05 | 4/04 | 7/03 | 9/04 | 12/06 | 9/04 | 9/06 | 7/03 | 7/03 | 8/04 | 8/04 | 8/04 | 10/04 | 9/04 | 11/06 | 12/06 | 10/06 | 9/04 | 8/04 | 8/04 |
| pH (units) | NA | 6.8 | 7.3 | 6.9 | 7.3 | 7.9 | 7.5 | 7.4 | 7.2 | 6.9 | NA | 7.7 | 7.5 | 8.6 | 7.5 | 7 | 8 | 7.5 | 7.3 | 7.1 |
| Alkalinity (mg/L CaCO3) | 379 | 54 | 235 | 85 | 162 | 137 | 337 | 304 | 344 | 141 | 319 | 424 | 82 | 65 | 137 | 681 | 147 | 384 | 302 | 363 |
| Hardness (mg/L CaCO3) | NA | 92.7 | 83.2 | 25 | 163 | 156 | 255 | 228 | 513 | 252 | 381 | 246 | 40 | 53 | 108 | 481 | 154 | 346 | 752 | 360 |
| Turbidity (NTU) | 2 | NA | NA | 0.2 | 0.7 | 0.4 | 5.8 | NA | NA | 2.3 | 23 | 7 | 0.9 | 0.1 | 2.6 | 35 | 1.5 | 20 | 7.1 | 30 |
| TOC (mg/L) | NA | <0.5 | <0.5 | <0.7 | <1** | <0.7 | 1.6 | <1.0 | <1.0 | 2.5 | <1.0 | 7.2 | 1 | <0.7 | <1 | 9.0 | <1 | 1.8 | 2 | 3.9 |
| Chloride (mg/L) | 110 | 41 | 51 | 1.2 | 1.0 | 51 | 2.0 | 190 | 82 | 130 | 14 | 7.2 | 2.1 | 7.6 | 23.0 | 7.0 | 14.0 | <1.0 | 34 | <1.0 |
| Sulfate (mg/L) | 1 | 12 | 74 | 5.8 | 2 | 20 | 2 | 120 | 390 | 1 | 27 | <5.0 | 17 | 18 | 6 | <1 | 21 | <1.0 | 410 | <5.0 |
| Silica (mg/L SiO2) | 16.7 | 19.7 | 8.1 | 25.7 | 15 | 12.3 | 13.9 | 27.3 | 29.4 | 11.1 | 19.4 | 26.6 | 14.5 | 10.7 | 13.3 | 20.1 | 12.7 | 14.3 | 29.7 | 25 |
| As tot. (μg/L) | 34.5 | 39.2 | 14.2 | 32.7 | 23.9 | 30 | 26.9 | 38.7 | 147 | 13.4 | 24.6 | 41.7 | 36.7 | 37.7 | 15.4 | 28.3 | 28.4 | 20.1 | 13.9 | 25.3 |
| As sol. (μg/L) | NA | 44.1 | 12 | 33.1 | 23 | 30.1 | 18.1 | 34.6 | 126 | 13.2 | 24.3 | 32.9 | 36.6 | 38 | 13.6 | 21.2 | 28 | 20.5 | 12.6 | 20.7 |
| As part. (μg/L) | NA | <0.1 | 2.2 | <0.1 | 0.9 | <0.1 | 8.8 | 4.2 | 20.3 | 0.2 | 0.3 | 8.8 | 0.1 | <0.1 | 1.8 | 7.1 | 0.4 | <0.1 | 1.3 | 4.6 |
| As (III) (μg/L)* | NA | 0.5 | 11.2 | 0.8 | 0.5 | 1.5 | 12.6 | 34.8 | 121 | 11.1 | 24.7 | 31.9 | 31.9 | 33.4 | 6.0 | 17.4 | 25.8 | 19.1 | 5.1 | 13.6 |
| As (V) (μg/L)* | NA | 43.6 | 0.8 | 32.3 | 22.5 | 28.6 | 5.5 | <0.1 | 5.3 | 2.1 | <0.1 | 1 | 4.7 | 4.6 | 7.6 | 3.8 | 2.2 | 1.4 | 7.5 | 7.1 |
| Fe tot. (μg/L) | 317 | <25 | 127 | <25 | <25 | <25 | 1547 | 546 | 1325 | 466 | 1615 | 1344 | 125 | <25 | 332 | 2659 | 157 | 1499 | 854 | 3078 |
| Fe sol. (μg/L) | NA | <25 | 118 | <25 | <25 | <25 | 855 | 540 | 1316 | 465 | 1635 | 1359 | <25 | <25 | 129 | 2350 | 151 | 1400 | 844 | 3149 |
| Mn tot. (μg/L) | 55.4 | 2.1 | 13 | 13.5 | 2.8 | 5.1 | 53.5 | 128 | 675 | 32.4 | 18.5 | 27 | 5.6 | 10.3 | 180 | 18.9 | 61 | 20.2 | 327 | 150 |
| Mn sol. (μg/L) | NA | 1.5 | 15 | 2.8 | 0.8 | 4.2 | 53.1 | 130 | 665 | 32.6 | 18.8 | 28 | 5.5 | 9.6 | 165 | 18.4 | 66.3 | 18.3 | 331 | 154 |
| Ca tot. (mg/L) | 12 | 28.3 | 20.6 | 7 | 49.9 | 28 | 57.9 | 60.6 | 148 | 56 | 89 | 56 | 11.2 | 18 | 35.6 | 103 | 50 | 71.4 | 173 | 87 |
| Mg tot. (mg/L) | 3.2 | 5.3 | 7.7 | 2 | 9.3 | 21 | 26.7 | 18.5 | 35 | 27 | 39 | 26 | 2.9 | 2 | 4.7 | 54 | 7.1 | 40.7 | 78 | 35 |
NA: Not analyzed.
*
The sum of As(III) and As(V) equals As sol.
**
Sample analyzed outside of holding time