257.5 mg/L = 257.5 ppm
| mg/L | ppm |
|---|---|
| 242.5 mg/L | 242.5 |
| 247.5 mg/L | 247.5 |
| 252.5 mg/L | 252.5 |
| 257.5 | 257.5 |
| 262.5 mg/L | 262.5 |
| 267.5 mg/L | 267.5 |
| 272.5 mg/L | 272.5 |
257.5 mg/L = 257.5 ppm
1 ppm = 1 mg/L (aqueous, density ≈ 1 kg/L) · 1 ppb = 0.001 mg/L · 1% = 10,000 ppm