Table 3.
Heavy metal pollution index (HMPI) and decreased percentage of studied metal in Thamirabarani River for Pre-lockdown and Lockdown phase.
| Sampling Point |
Pre-lockdown phase |
Lockdown phase |
Decreased % (Pre lockdown – Lockdown) | ||
|---|---|---|---|---|---|
| Pre lockdown | Degree of pollution as per HMPI scale | Lockdown | Degree of pollution as per HMPI scale | ||
| TSW 1 | 48.23 | High Pollution | 35.97 | High Pollution | 25.41 |
| TSW 2 | 76.41 | High Pollution | 39.72 | High Pollution | 48.02 |
| TSW 3 | 25.60 | Medium Pollution | 19.62 | Medium Pollution | 23.36 |
| TSW 4 | 34.97 | High Pollution | 30.03 | Medium Pollution | 14.14 |
| TSW 5 | 81.25 | High Pollution | 39.62 | High Pollution | 51.23 |
| TSW 6 | 38.65 | High Pollution | 30.08 | Medium Pollution | 22.17 |
| TSW 7 | 15.18 | Medium Pollution | 10.67 | Low Pollution | 29.68 |
| TSW 8 | 46.75 | High Pollution | 11.47 | Low Pollution | 75.46 |
| TSW 9 | 48.04 | High Pollution | 12.25 | Low Pollution | 74.49 |
| TSW 10 | 46.36 | High Pollution | 14.73 | Low Pollution | 68.23 |
| TSW 11 | 78.95 | High Pollution | 37.42 | High Pollution | 52.60 |
| TSW 12 | 81.25 | High Pollution | 39.62 | High Pollution | 51.23 |
| TSW 13 | 69.68 | High Pollution | 43.38 | High Pollution | 37.74 |
| TSW 14 | 43.56 | High Pollution | 39.49 | High Pollution | 9.35 |
| TSW 15 | 29.79 | Medium Pollution | 22.12 | Medium Pollution | 25.77 |
| TSW 16 | 59.43 | High Pollution | 34.55 | High Pollution | 41.86 |
| TSW 17 | 50.72 | High Pollution | 44.07 | High Pollution | 13.10 |
| TSW 18 | 51.87 | High Pollution | 46.92 | High Pollution | 9.55 |
| TSW 19 | 66.81 | High Pollution | 42.67 | High Pollution | 36.14 |
| TSW 20 | 51.86 | High Pollution | 43.40 | High Pollution | 16.32 |
| Min | 15.18 | Low Pollution (0%) | 10.67 | Low Pollution (20%) | 9.35 |
| Max | 81.25 | Medium Pollution (15%) | 46.92 | Medium Pollution (20%) | 75.46 |
| Mean | 51.81 | High Pollution (85%) | 31.61 | High Pollution (60%) | 36.85 |