WATER ENVIRONMENTS IN THE SOUTHERN DELTA OF MYANMAR DURING THE RAINY SEASON

抄録

 Some diseases in Myanmar during the rainy season are related to the water environment and the water quality. In order to contribute to ensuring safe water supply, we collected and analyzed water samples in Myanmar in September 2011. Early research had already reported that coliform and E. Coli were detected in all the survey areas. We examined the water quality, especially chemical components harmful for health, and classified the sample waters into water quality-types in order to identify the sources and contamination. We obtained the following results: (1) Some tube well, dug well, and filtered waters were estimated to be contaminated and unsuitable for drinking and domestic water. (2) Waters at elevation less than about 10 m were more likely to be polluted. (3) The chemical components beyond the drinking water guideline values of World Health Organization (WHO) for health were NO₂^-, NO₃^-, Pb²⁺, and Mn²⁺. (4) For the taps with longer direct distance from the pumping station and lower elevation, there were several cases in which the tube well water geographically close to the tap intruded into the tap of filtered water. Then, we suggested some recommendations for water treatment based on WHO guidelines, and we also suggested the desirable improvements to the water supply systems. The first potential approach to treatment of drinking water supplies is to dilute the contaminated water with a low-contaminated source (e.g., high-elevation reservoirs). The desirable improvement to the water supply systems are as follows: (a) piping routes from reservoir to user places should be maintained as sanitary and clean, and (b) tube well water systems should be improved to prevent the intrusion of contaminants.