| Sample | Location |
| W1 (public tap water) | Molete, Ibadan. |
| W2 ( bore hole water) | Molete, Ibadan. |
| W3 ( well water) | Molete, Ibadan. |
| W4 (public tap water) | Jericho, Ibadan. |
| W5 (borehole water) | Jericho, Ibadan. |
| W6 (well water) | Jericho, Ibadan. |