Table 3: Permissible limits of some heavy metals in water in Wastewater Forum, WHO and Standard Organization of Nigeria.
Standard |
(WWF) |
(WHO) |
(SON) |
Mg/L |
|||
Lead, Pb |
0.1 |
0.01 |
0.01 |
Cobalt, Co |
|
0.005 |
|
Nickel, Ni |
0.2 |
0.07 |
0.02 |
Chromium, Cr |
0.01 |
0.05 |
0.05 |
Copper, Cu |
0.2 |
2 |
1 |
Cadmium, Cd |
0.01 |
0.003 |
0.003 |
Source: WWF: 2007; WHO: 2008 and SON: 2016