Status of bacteriological, hydrocarbon and heavy metal pollution on lake Tanganyika and pollution's effect on public health in Mpulungu area, Zambia

Abstract

This study investigated bacteriological, hydrocarbons and heavy metal pollution status on Lake Tanganyika in Mpulungu area in the period of October 1999 to March 2000. The purpose of this study was to identify the origin and sources of bacteriological, hydrocarbon and heavy metal pollution on the lake. The objectives were to (i) identify the sources and causes of bacteriological, oil and heavy metal pollution; (ii) determine the magnitude of bacteriological, oil and heavy metal pollution in the lake water; and (iii) assess the epidemiological pattern of water-borne diseases in Mpulungu area.The responses from interviews with the people generally revealed that there are waste materials being introduced on the lake by local people as well as fishing companies. Since many people depend on the lake water for domestic use, chances are that there is a relationship between the quality of water and the spread of water related diseases in the area.In order to determine the status of the water in Mpulungu in terms of bacteriological pollution,samples of lake and river water were analysed for coliform bacteria because this type of bacteria is used as an indicator organism for bacteriological pollution. To determine the amount of oil and heavy metals in the lake water, sediments were analysed using acetone/chloroform and Flame Atomic Absorption respectively. Analysis of data revealed that none of the five sampling stations, on the lake, namely, Mbete Bay,Musende Bay, Ngwenya/Harbour, and Lunzua River road bridge and one township tap, had coliform bacteria below the WHO Permissible Standard for Drinking Water of 0 colonies/100 m/s.Musende Bay where all fishing companies and the harbour are situated, recorded the highest percentage of oil/g in sediments of 0.4 %/g, which was above zero Maximum Permissible levels of oil for WHO Guidelines for Drinking Water. During the study, it was found that there was a strong relationship between the percentage of oil in sediment and the percentage of fine grains in sediments.The study found that there were minute or close to zero concentrations of copper and aluminum in Mpulungu Bays. Chituta Bay was found to contain lead at the level of (0.04mg/l) above the Maximum Permissible levels according to WHO Guidelines for Drinking Water of O.Olmg/1. It is concluded that though at slow rate and in small concentrations, Lake Tanganyika is actually receiving substances, which might degrade and destroy the lake permanently. Lake Tanganyika being in a rift valley and located in the tropics has very high temperatures throughout the year.This high temperature favour the growth of some dangerous pathogens and also favours the decomposition of material.It is recommended that Mpulungu Township Council should improve the water purification system, and set up good wastewater and solid waste control strategies. Finally there is need for more research on lead pollution, the relationship between water-borne diseases and coliform bacteria in the water and the assessment of the effect of pollution on biodiversity in the area.