| T value and significance | ||||||
| Hg | As | Pb | Cd | Zn | Cu | Cr |
January | 5.53*** | 4.55*** | 1.69 NS | 3.15** | 1.56 NS | 3.67*** | 2.23* |
April | 3.44** | 2.16* | 3.94*** | 1.47 NS | 1.27 NS | 2.31* | 3.05** |
July | 4.95*** | 2.22* | 3.44** | 1.19 NS | 1.76 NS | 3.76*** | 3.5*** |