HEAVY METAL DETERMINATION IN NASOLO RIVER BLANTYRE

Heavy metals are metals with high densities and atomic weights. Heavy metal contamination in water systems is a severe concern all over the world, particularly in locations where anthropogenic pressures are considerable (Ochieng, 2007). In Malawi studies of heavy metals in our river systems is not an area of much interest, because it is thought that their concentrations do not exceed the recommended limits by MBS and WHO. In this context, a study was conducted to evaluate the amounts of heavy metals in the Nasolo river sediments, one of Blantyre's streams. The river is significant because it provides water for a variety of domestic purposes and serves as a habitat for aquatic organisms. This river also has a catchment with the Mudi River, from which Blantyre Water Board gets its raw water. The H0 hypothesis was that the analyzed metals do not deviate considerably from the set standards. The study collected sediment samples from seven different locations, including the source, ndirande view, chioni bridge, paseli lodge, industrial area, and railway residences. With the exception of pH, samples were analyzed for heavy metal concentrations using atomic absorption spectrometry in the laboratory, and physical parameters such as TDS and EC were obtained on-site. Zn, Cd, Fe, Pb, and Cu were identified in the metal analysis. The findings were compared to the Malawi Bureau of Standards' (MBS, 2005) and World Health Organization's (WHO) drinking water quality standards. The average mean concentrations were, Zn(0.61mg/l), Cu(0.523mg/l), Pb(0.0342mg/l), Fe(1.796mg/l), and Cd(0.006mg/l). Cu, and Zn all fell within the MBS recommended range, however Cd, Pb and Fe did not. pH values, with the exception of TDS, were 6.2-8.0, EC (8.2-32.7 μS /cm), and TDS (389-494 mg/l), all of which were within the WHO and MBS recommended ranges. To better understand the level of pollution, contamination factor was calculated, Pb (0.0213), Fe(0.0189), Cd(1.1195E-5), Cu(0.0544) and Zn(0.0034).This indicates that nasolo river water is not highly polluted because CF values were all less than 1. The results also showed that the pairs of Zn and Pb, Cu and EC, Cd and Zn, Pb and Fe, TDS and Fe were highly correlated. This study will give a baseline that Blantyre city assembly and the department of environmental affairs work together to prevent further river system degradation.

In Malawi studies of heavy metals in our river systems is not an area of much interest, because it is thought that their concentrations do not exceed the recommended limits by MBS and WHO. With the exception of pH, samples were analyzed for heavy metal concentrations using atomic absorption spectrometry in the laboratory, and physical parameters such as TDS and EC were obtained on-site. pH values, with the exception of TDS, were 6.2-8.0, EC (8.2-32.7 μS /cm), and TDS (389-494 mg/l), all of which were within the WHO and MBS recommended ranges. To better understand the level of pollution, contamination factor was calculated, Pb (0.0213), Fe(0.0189), Cd(1.1195E-5), Cu(0.0544) and Zn(0.0034).This indicates that nasolo river water is not highly polluted because CF values were all less than 1.

The research was conducted on Nasolo River which runs through Ndirande area and makata area and feeds into mudi river in Blantyre. The map below shows the sampling points indicated by dots along the nasolo stream. The sampling points coordinates using a GPS machine shown in the appendix at each and every sampling point.

Traditional authority: Blantyre City

District: Blantyre

Coordinates: -15.7955, 35.04405