Things I found out about Hanoi when looking for teaching materials for my students

The sustainability of toilets in Hanoi, Vietnam
Summary
The sewage/drainage system for Hanoi was installed over 50 years ago by the French colonialists for 400,000 people. The same pipelines are still in use today but cater for over 1.6 million people. Sewage is not treated. All sewage, waste water (including waste water from hospitals, industrial waste) etc. are sent through a joint sewage and drainage system, polluting the lakes scattered through the city and the rivers.

Groundwater pollution in the Hanoi area, Vietnam
Summary
Hanoi's water supply is mainly ground-water. Pollutants found are nitrogen - at a serious level, mercury, arsenic and biological elements (fecal coliform). Studies for benzene, toluene, and chloride are incomplete at the time the paper was published.

Assessment of Heavy Metal Pollution in River Water of Hanoi, Vietnam Using Multivariate Analyses
This paper shows the concentration of heavy metals in table formats.

The Economy and the Traffic Are Humming in Hanoi, but the Price Is Dirtier Air
Basically says that only China and India have more pollution of the very dangerous microscopic dust called PM10, than Hanoi. Hanoi has double that found in Bangkok. Bangkok's air is cleaner than Hanoi!!!

Source of the above article here: It's very interesting and readable with lots of pictures.
"An Air Quality Management Action Plan for Hanoi"

Measures urged to curb traffic pollution
A news article stating "... air pollution is soaring in cities, doubling or tripling the permitted levels. It is estimated to cost people in Ha Noi $60 million a year to treat health problems related to the pollution and $120 million in HCM City".
"Some researchers predict that in the absence of tough measures the number of motorbikes in Viet Nam will increase to 30 million by 2020, compared to 18.5 million in 2006".

And again, the weblinks are on my work computer - I also found that there are huge amounts of arsenic in the water, and 2 types of e-coli, and cadmium and I can't remember what else.

I was boiling the tap-water for my tea and coffee at home until Victor got here and suggested I use bottled water instead. Thank you Victor. But please do not worry about my mutating cells, as I'm hardly ever at home, I didn't really drink very much tea or coffee at home over the first month.