Table 3.
Concentration of some heavy metals in drinking water samples, Serbo town and its surroundings, October (2011)
| Heavy metal | Conc. | Water source | Standards | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Tap water | protected wells | Unprotected wells | Protected spring | Unprotected springs | p- value | WHO | USEPA | ||
| Lead (mg/l) | Mean | 0.03 | 0.02 | 0.03 | 0.02 | 0.02 | 0.64 | 0.01 | 0.015 |
| SD | 0.03 | 0.01 | 0.02 | 0.01 | 0.03 | ||||
| %CV | 104.1 | 34.40 | 55.86 | 91.88 | 176.47 | ||||
| Min | BDL | 0.01 | 0.00 | BDL | BDL | ||||
| max | 0.09 | 0.04 | 0.07 | 0.04 | 0.08 | ||||
| Zinc (mg/l) | Mean | 0.19 | 0.13 | 0.02 | 0.02 | 0.03 | 0.003 | 5.00 | 5.00 |
| SD | 0.13 | 0.11 | 0.02 | 0.03 | 0.04 | ||||
| %CV | 67.28 | 87.81 | 108.74 | 174.32 | 141.90 | ||||
| Min | 0.06 | 0.02 | 0.00 | 0.00 | BDL | ||||
| max | 0.41 | 0.27 | 0.06 | 0.07 | 0.14 | ||||
BDL below detection level