Surface water quality and information about the environment surrounding Inle Lake in Myanmar

Inle Lake is the second largest lake in Myanmar and one of the nine key sites for sightseeing there. An analysis of its water quality has not been published before. The objective of this study is to reveal the current situation and find any major problems with the lake. For this purpose, the natural and cultural environments were examined. Some physical and chemical aspects of the surface water were assayed in situ for 2 days in November 2004. The principal ions were analyzed in our laboratory. The main cation and anion species in the lake surface water are Ca²⁺ and HCO₃ ⁻. Its high calcium content can be attributed to the limestone of Shan Plateau around the lake. The alkalinity of the lake water was 3829–4114 acid-neutralizing capacity (ANC) (pH 7.8–8.0); it can be attenuated by Ca²⁺. The concentrations of PO₄-P, NO₂-N, and NO₃-N were relatively high; these could originate from domestic and agriculture uses. The trophic state is eutropic. The concentrations of coliform bacteria indicated that the lake water was unfit to drink, but some people use it for drinking anyway. The bacteria could enter the lake through the direct latrine system used there. The thermal type of the lake is presumed to be warm polymictic. More extensive studies are needed because the lake is thought to be the most changing site in Myanmar as a result of both the tourism boom and increasing agricultural activity.