Impact assessment of global environmental changes on safety and stability of water systems in Asian coastal mega cities

2004年对胡志明市污染河流进行了病原微生物调查。结果发现，胡志明市受污染河流中大肠菌群和病毒的浓度与日本污水的浓度相同。2005年1月和2月对Chiliwung河沿岸社区的洪水对健康的影响进行了调查，得出以下结论：1)被洪水污染的浅层地下水是被洪水污染的主要饮用水来源。(2)洪水进入民居停留时间长，大肠菌群水平高于赤潮江；(3)洪水区腹泻、皮肤病和流感病例明显高于非洪水区。本次调查的结果表明，洪水事件除了造成溺水等直接损害外，还迫使当地居民长时间撤离，并带来健康影响。2005年，胡志明市进行了一项与雅加达类似的洪水调查。2006年，我们沿西贡河及流入西贡河的运河进行水质监测。西贡河没有潮汐闸；因此，由于潮汐的波动，水位波动很大。胡志明市没有中央污水处理厂，生活废水和工业废水都要经过沉淀等简单处理后才能进入西贡河。因此，从胡志明市流出的污染水上升到城市取水点。如果由于全球环境变化导致水位上升，雅加达和胡志明市等亚洲沿海大城市将遭受更严重的洪水灾害，对健康造成影响的病例也将增加。

In 2004, a survey on pathogenic microorganisms in contaminated river in HCMC was conducted. As a result, the concentration of coliform group and viruses in contaminated rivers in HCMC was found to be the same level as sewerage in Japan. In 2005, a survey was conducted in January and February, on the health impact of flooding in the communities along the Chiliwung River, and the following conclusions were obtained:1)The major source of drinking water in the flooded are is shallow groundwater, which was contaminated with flood water.2)The flood water that went into houses stay long hours, and the levels of coliform group were higher than Chiliwung River.3)In the flooded area, the cases of diarrhea, skin diseases and influenza, were much higher than in the non-flooded area.As a results of this survey, it was concluded that, in addition to the direct damage such as drowning, flood events force the local residents a long evacuation lives, and bring about health impacts.In 2005, a similar flood survey as Jakarta was conducted in HCMC. In 2006, water quality monitoring was conducted along Sai Gon River and canals that flow into Sai Gon River. There is no tidal gate in Sai Gon River; hence the water level fluctuates a lot due to tidal fluctuation. There is no central wastewater treatment plant in HCMC, and both domestic and industrial wastewaters go Sai Gon River only after simple treatment like sedimentation. Hence it was found that the contaminated water from HCMC goes up the point of the city's water intake. If the water level goes up due to Global Environmental Changes, Asian coastal mega-cities such as Jakarta and HCMC will suffer more severely from flood events, and the cases of health effect will go up.