Bacteriological analysis of Lake Toba

Abstract

Abstract Lake Toba is designated as a National Tourism destination in North Sumatra. Lake Toba also used as a domestic water source for the surrounding communities, so that studies on water quality especially bacteriological condition need to be carried out. Theaims of this study was to analysis heterotrophic bacteria, E. coli, and total coliform bacteria. In addition, somephysico-chemicalparameters were also studied. Water samples were taken from ten different sampling stations from the eastern, western, northern and southern sides of Lake Toba. Heterotrophic bacteria was analyzed using the spread plate method, the total number count of E.coli and coliform were analyzed using the filtration method.The results showed that physico-chemicalparameters meet the Indonesian water quality criteria of raw materials for drinking water and recreation except the COD. None of samples conformed to Indonesian water standard for sanitation hygiene needs for E. coli densities should not exceed 0 colonies / 100 mL and the total coliform not exceed 50 colonies / 100 mL.The highload of COD, E.coli and total coliform indicated severe contamination of lake with domestic sewage and human excreta. Thus we assumed that water from Lake Toba is not safe for domestic water sources.