638.5 mg/L = 638.5 ppm
| mg/L | ppm |
|---|---|
| 623.5 mg/L | 623.5 |
| 628.5 mg/L | 628.5 |
| 633.5 mg/L | 633.5 |
| 638.5 | 638.5 |
| 643.5 mg/L | 643.5 |
| 648.5 mg/L | 648.5 |
| 653.5 mg/L | 653.5 |
638.5 mg/L = 638.5 ppm
1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm