Environmental Engineering Reference
In-Depth Information
Figure 11.3. Map of the study area and
sampling points' location.
sampling and the transportation to all the sampling points. Samples were preserved in a
cooler box with ice cubes to maintain a low temperature during the transportation to the
laboratories.
Samples were analyzed at the LWB laboratory and the Central Water Laboratory. The
LWB laboratory carried tests for pH, EC, TC and TDS. The Central Water Laboratory
carried out the tests for nitrates, phosphates, BOD, and COD, according to the Standard
Methods (1994).
The results were compared with the water quality standards in Malawi and the WHO
guidelines on drinking water quality, because many of the people in the study area use the
water in the rivers directly without any treatment. Samples for nutrient analyses were
filtered through a 0.45 nm filter paper to allow the determination of only dissolved
nutrients and were analyzed within 24 hours of sampling. Samples for TC were collected
in sterile bottles.
The analysis of samples was done within 6 hours of sampling. Nitrates and phosphates
were measured using the Ultra Violet Direct Reading method by a multipurpose HACH
DR/4000 UV - VIS Spectrophotometer, with a range of 0-10.2 mg/l. The “Potassium
