In Vietnam, the Red River Delta and the Mekong Delta are two of the most densely populated regions in the world. These two Deltas has a population density of about 1,300 people/km2 covering an area of some 15,000 km2 (Red River Delta) and 500 people/km2 covering an area of some 39,000 km2 (Mekong Delta). Of the 38 million people that live near there, nearly 25 million have no access to public water supply and are therefore depending on other drinking water and other daily usage resources such as river surface water.
Due to pathogen-contaminated surface river water, they developed symptom of cholera, dysentery and other infection diseases. To combat these diseases, UNICEF encourage the digging for private tubewells in VietNam. Currently, there are over 1,000,000 tubewells in operation and the numbers are rapidly increasing.
Unfortunately, much of the groundwater extracted from these shallow alluvial aquifers (<150 m) is often enriched in arsenic.
Arsenic contamination of shallow groundwater is among the biggest health threats in the developing world, especially in South and Southeast Asia (Bengal delta, Vietnam, Cambodia, Myanmar, and Sumatra). Given that groundwater is the main source of drinking water, many large-scale groundwater survey covering the entire Red River Delta by different organization has shown an alarming results that over 65% of these studied well exceed the World Health Organization (WHO) guidelines for safe drinking water.
There are little over 1 million tubewells in Bangladesh as 97% of the population depends on its to access water due to the easy availability of aquifers, low-technology installation procedure and affordable cost. But little did they know that >50% of those tubewells water contaminated with arsenic level ablove 50 ppb (WHO standard is 10 ppb) where one in five death in Bangladesh is related to arsenic.
The arsenic problem in Vietnam has only got worse. Since 2006, the United Nations body has warned against arsenic contamination in groundwater in Vietnam. Recently, a WHO report stated "The Red River Delta potentially exposes over 11 million people to elevated levels of arsenic and similar geological conditions exist elsewhere in the country including the highly populated Mekong Delta. And in the most extreme cases, some wells in the Red River Delta yielded sample containing 3,000 ppm or 300,000 times above the safe drinking level.