Heavy Metal | Frequency | p value (<0.05) | |||
Winter | Summer | ||||
Positive | Negative | Positive | Negative | ||
Ni | 45 | 49 | 47 | 47 | 0.88 |
Cu | 45 | 49 | 47 | 47 | 0.88 |
Pb | 47 | 47 | 44 | 50 | 0.0645 |
Cd | 4 | 90 | 12 | 82 | 0.7705 |