Table 1.
Hydrochemical properties of water from Nyabarongo and Nyabugogo rivers, Rwanda
| Parameter | Nyabarongo river | Nyabugogo river | WHO guidelines [14] | |
|---|---|---|---|---|
| Ruliba station | Kirinda bridge | Giticyinyoni | ||
| Temperature (℃) | 22.6 ± 0.30 | 23.0 ± 0.26 | 22.5 ± 0.40 | 25.0 |
| pH | 8.15 ± 0.07 | 7.96 ± 0.06 | 8.22 ± 0.03 | 6.5–8.5 |
| Conductivity (μ/Scm) | 74.3 ± 3.84 | 20.0 ± 0.15 | 102.0 ± 1.0 | 1000 |
| TDS (mg/L) | 39.0 ± 2.0 | 10.0 ± 0.01 | 52.9 ± 0.36 | 2000 |
| Total nitrogen (mg/L) | 1.62 ± 0.02 | 1.56 ± 0.001 | 12.81 ± 9.51 | 3.0 |
| Nitrite nitrogen (mg/L) | 0.01 ± 0.00 | 0.017 ± 0.02 | 0.014 ± 0.003 | 0.1 |
| Nitrate nitrogen (mg/L) | 0.40 ± 0.01 | 1.39 ± 0.01 | 1.07 ± 0.058 | 10 |
| Ammoniacal nitrogen (mg/L) | 0.153 ± 0.015 | 0.117 ± 0.01 | 0.12 ± 0.006 | 0.5 |
| Sulphates (mg/L) | 0.58 ± 0.017 | 0.270 ± 0.02 | 0.86 ± 0.03 | 1000 |
| Phosphates (mg/L) | 0.42 ± 0.01 | 0.21 ± 0.02 | 0.39 ± 0.058 | 5.0 |
| Fe (mg/L) | 1.61 ± 0.03 | 0.63 ± 0.02 | 1.57 ± 0.02 | 0.3 |
| Mn (mg/L) | 0.53 ± 0.002 | 0.02 ± 0.002 | 0.49 ± 0.03 | 0.1 |
| Cu (mg/L) | 0.24 ± 0.02 | BDL | 0.29 ± 0.058 | 0.5 |
| Zn (mg/L) | BDL | 0.09 ± 0.01 | 0.43 ± 0.058 | 3.0 |
| Cr (mg/L) | BDL | 0.06 ± 0.002 | 0.15 ± 0.00 | 0.05 |
| Cd (mg/L) | 0.106 ± 0.002 | BDL | BDL | 0.01 |
| Pb (mg/L) | 0.051 ± 0.01 | 0.75 ± 0.02 | 0.59 ± 0.058 | 0.01 |
BDL below method detection limit
Values in italics indicate exceedance of WHO limits