Determination of heavy metal pollution in Lake Victoria using energy dispersive X-ray fluorescence (EDXRF) analysis.

This work presents the energy dispersive x-ray fluorescence (EDXRF) analysis of water and plant samples from Lake Victoria at Mwanza for heavy metal pollution. A brief description of the EDXRF technique, and an account on water and plant sample preparation for EDXRF analysis is given. Typical detection limits of the EDXRF system for most of the elements in water are 0.62 - 0.88 mg/1. The overall precision and accuracy of the technique is presented. Water and plant (Water hyacinth) samples were collected from Lake Victoria around Mwanza municipality, at the locations named Mwanza south, Mwanza central, and Mwanza north. Mwanza north was found to record a relatively higher concentration levels of Cr, Zn, Pb, Mn and Fe than Mwanza south and Mwanza central. Maximum concentration values of up to 1640mg/1 for Fe, 860mg/1 for Mn, 42.8mg/1 for Cr, 15.1mg/1 for Pb, 742.5mg/1 for Zn, and 23.3mg/1 for Cu, were observed at Mwanza north. Possible sources of the elements are discussed, from which industrial effluents, soil erosion and sewage disposal were seen to be the most probable. A comparison with the international guidelines for drinking water reveal that iron and manganese have higher values than the international acceptable levels. However, the rest of the determined elements are found to be within the acceptable concentration levels.