Arsenic and Old Lace

Hanoi has a problem with arsenic. Now it’s entered the water system. Words and photos by Nick Ross


Aron shows me an email. It doesn’t make for good reading.


“My girlfriend and I have been living in Hanoi for six years,” goes the writer. “We are suffering from most of the symptoms of arsenic poisoning, so I’m concerned it’s related to the water here. We have been out of the country for the last month and the symptoms have gone away.”


The Vietnam distributor of the German-made water filter brand, BWT, over the past year Aron has discovered that his experience is not unique. Recently he was called into a villa compound in the Long Bien area of Hanoi to test the water. The World Health Organization (WHO) recommends a limit of 0.01 mg/litre (10 parts per billion) of arsenic in drinking water. The results from Aron’s test showed that during two different periods in February, the level of arsenic was between 41 and 43 percent above the safe limit. Which suggests that this metalloid has got into the city’s water system.


The Red River Delta in northern Vietnam as well as places as far flung as Chile, Bangladesh, Mongolia, Taiwan and even the western US are known to contain large deposits of arsenic. Buried deep inside the earth’s crust, the various forms of this metalloid are normally harmless, unless they manage to get into the water. Here it seemed that this was exactly what had happened.


Yet was this an anomaly, a one off? Or is the whole of the city affected by contamination?


We decided to find out for ourselves. With a home testing kit in hand, Aron and I spent a day testing the water in Hanoi.




In mid-January I came down with what I thought was food poisoning. Yet the sudden bout of nausea, diarrhoea and acute headaches didn’t make sense. The night before I’d eaten banh mi trung at a place in the Old Quarter I’d frequented for over a decade. The next morning I ate bun bo nam bo at a West Lake eatery, also a regular haunt. Neither place had ever given me food poisoning.


Yet two days in and I was getting worse. I was dehydrated, constantly tired and had odd bouts of dizziness. So I went to the hospital, had a blood test and spent two hours on a drip. When the results came back I neither had a virus nor a bacterial infection. The doctors suggested that maybe I didn’t have food poisoning after all. As I started researching this article, I found another possible source for my mysterious illness; arsenic. It was uncanny.


The symptoms of arsenic poisoning start with headaches, confusion, severe diarrhoea and drowsiness, while acute levels of the metalloid can lead to diarrhoea, vomiting, vomiting blood, blood in the urine, cramping muscles, hair loss, stomach pain and convulsions. The final result is coma and death.


I was fortunate. After a week I was back to normal, but it did make me ask a question. Historically Hanoi has had a water shortage. To make up for the lack of water, large numbers of houses have wells. It is these wells, dug deep down into the earth and into the layer where there is a concentration of arsenic, that bring the metalloid up to the surface. Could I have eaten something made with contaminated well water? Or as Aron had speculated over several phone conversations, could the whole of the city’s water system be at fault?


This is exactly what has happened in Bangladesh over the past 35 years. Millions of tube wells were drilled in the 1970s to provide villagers with clean water, but many of them were dug into shallow layers of ground that had naturally occurring arsenic, contaminating the water. A recent study led by Dr. Habibul Ahsan of the University of Chicago found that as many as 77 million people — half the population — may have been exposed to toxic levels of arsenic. The study followed nearly 12,000 Bangladeshis for over a decade and discovered that more than 20 percent of deaths were caused by arsenic.


The Tests


We started our journey with two samples from the Tay Ho area of West Lake. One came from a restaurant that uses pre-filtered water. The other from West Lake itself. After putting in three doses of different chemicals to the testing bottle, shaking and waiting 20 minutes, the litmus paper with the restaurant water turned a very light yellow. The water was contaminated with arsenic, but it was just on the limit. This was commensurate with some recent tests Aron had conducted of the water at the Syrena Centre on Xuan Dieu — 0.088 mg/l and 0.094 mg/l, both just under the WHO limit.


The water from West Lake, however, was surprisingly untainted — the test showed the arsenic levels at 0.005 mg/l. “Maybe it’s time to drink water from West Lake,” Aron joked. Considering that raw sewage gets pumped into the lake, the thought was horrific. Could West Lake water turn out to be safer than tap water?


Experiment number two was also conducted in the West Lake area, but this time with melted ice. One batch came from a restaurant that buys the ice in, the other from a place that makes it on-site. Both came back with low levels of arsenic — around the 0.003 mg/l to 0.005 mg/l. What was interesting was the ice that was ‘bought in’.


With water supply a problem in Hanoi, our guess is that the ice was made outside the main city, thus meaning it used water not contaminated with the poison. Likewise, the ice made in house suggested that arsenic contamination varies from place to place, location to location.


We then headed to the Old Quarter and did our next test at an establishment that we know uses a well. The results were disturbing. Here contamination was high — somewhere between 0.025 mg/l and 0.05 mg/l. In other words, from two and a half times, to five times the acceptable limit. Whether the water we sampled came from the well or the water system, we couldn’t tell. But it would be fair to conclude that with so many wells in this area, if this restaurant is affected, then so will elsewhere.


What Does this Mean?


If my personal bout of sickness was indeed arsenic poisoning, then this is a worry. The problem is that because arsenic particles are so microscopic, they are among the hardest substances to filter out of the water system. Boiling makes no difference. Neither do standard water filtration systems.


If you do want to filter the substance out, then there are two expensive options.


The first solution is reverse osmosis. The system works by forcing water through a special, selective membrane. The membrane has microscopic pores that are specially sized to allow water molecules through, while trapping larger inorganic molecules like lead, iron, chromium and arsenic. Studies have shown that reverse osmosis can be up to 95 percent effective in the removal of arsenic.


The other option is an anionic exchange system. Using a physical or chemical process to exchange ions between a resin bed and water passing through, these systems soften water, remove iron and manganese, and lower nitrate and arsenic levels. Anionic exchange systems are usually point-of-entry systems, meaning that they treat all water coming into the home. However, they are very costly.


As many people can’t afford this, what other solutions are there?


“I believe arsenic can’t be absorbed through the skin,” says Aron, a fact backed up by the WHO, which states that any skin absorption is minimal. “This means that showering, washing your hands and so on is absolutely fine. However, you should brush your teeth with mineral water.”


Other things he suggests are avoiding bia hoi — or at least, bia hoi produced in Central Hanoi — and being careful about where you get your ice from. Coffee is another thing to avoid. It’s impossible to know whether the water is contaminated or not. As for pho and other noodle soups; same problem.


Ultimately if we live in Hanoi, we have to survive, lead normal lives. To avoid everything or anything that could potentially be contaminated with arsenic would be the equivalent of not living at all. We couldn’t go to restaurants or eat street food, as we wouldn’t know what water has been used for cooking and for washing the fruit and vegetables. Forget coffee or perhaps even non-imported beer. And as for water usage at home, we would find ourselves using La Vie or an equivalent for everything. Not only is it impractical, it’s impossible.


However, if you do feel you’ve contracted arsenic poisoning or if you’re worried about it, then perhaps it’s time to make some adjustments. Maybe move apartment or house — the water supply could be contaminated — or perhaps, as in my case, stop eating at two particular eateries. Or even better, test the water where you live to find out for yourself.





To find out more about what water filters are available, then information on Aron’s products, BWT, can be found at or at


His Hanoi showroom is on the ground floor of the Syrena Center Shopping Mall, 51 Xuan Dieu, Tay Ho, Tel: 0943 337633 or 0911 459033 

More in this category: « Saigon High Landing on Water »


  • Nick R
    Nick R Sunday, 03 April 2016 06:58 Comment Link

    Joe, read our previous article on the issue and this should give you some more background:

  • Joe
    Joe Saturday, 02 April 2016 14:29 Comment Link

    "The Vietnam distributor of the German-made water filter brand" is your only source?

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