Table 1 Summary of Nigerian and some international guideline values for drinking water samples
Parameter (element/ substance) | Nigerian guideline value (mg/ L) | WHO guideline value (mg/ L) | USEPA guideline value (mg/ L) | EU guideline value (mg/ L) |
|---|---|---|---|---|
Arsenic (As) | 0.01 | 0.01 | 0.01 | 0.01 |
Barium (Ba) | 0.7 | 0.7 | 2.0 | NA |
Cadmium (Cd) | 0.003 | 0.003 | 0.005 | 0.005 |
Chlorine (Cl − ) | 250 | 250 | 250 | 400 |
Chromium (Cr 6+ ) | 0.05 | 0.05 | 0.1 | 0.05 |
Chemical Oxygen Demand | NA | NA | NA | NA |
Conductivity (μS/ cm) | 1000 | NA | NA | NA |
Cyanide (CN − ) | 0.01 | 0.07 | 0.2 | 0.05 |
Hardness (as CaCO 3 ) | 150 | 180 | NA | NA |
Iron (Fe +2 ) | 0.3 | 0.3 | 0.3 | 0.2 |
Manganese (Mn 2+ ) | 0.2 | 0.4 | 0.05 | 0.001 |
Mercury (Hg) | 0.001 | 0.006 | 0.002 | 0.001 |
Nitrate | 50 | 50 | 10 | 50 |
Ph | 6.5-8.5 | 6.5-8.0 | 6.5-8.5 | 5.5-9.5 |
Phosphate (PO 4 3- ) | NA | NA | NA | NA |
Sodium (Na) | 200 | 200 | NA | 150 |
Sulphate (SO 4 2− ) | 100 | 250 | 250 | 250 |
Total Dissolved Solids | 500 | NA | NA | NA |
Zinc (Zn) | 3.0 | 3.0 | 5.0 | NA |