640.5 mg/L = 640.5 ppm
| mg/L | ppm |
|---|---|
| 625.5 mg/L | 625.5 |
| 630.5 mg/L | 630.5 |
| 635.5 mg/L | 635.5 |
| 640.5 | 640.5 |
| 645.5 mg/L | 645.5 |
| 650.5 mg/L | 650.5 |
| 655.5 mg/L | 655.5 |
640.5 mg/L = 640.5 ppm
1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm