Toxic pollution in water
61
Arsenic in “safe” water
For centuries, most people in Bangladesh drank surface water from carefully
protected ponds. But to bathe and wash dishes and clothes, they used
rivers, ditches, and other unprotected water sources. This water was often
contaminated with germs, causing diarrhea, cholera, hepatitis, and other
health problems. So the government worked with international agencies to build
shallow tube wells all over the country. Public health campaigns encouraged
people to use the “safe” groundwater from tube wells instead of surface water.
Soon there were fewer health problems from germs. But a large number of
toxic poisonings started to be reported around 1983. Many people got very sick
with skin sores (lesions), cancer, heart disease, and diabetes. Many people died.
No one knew what was causing these illnesses. By 1993, scientists agreed some
illnesses were caused by arsenic in the groundwater. Nobody had tested the
groundwater for arsenic. However, almost half the tube wells draw water with
too much arsenic in it.
How did the arsenic get into the water? Scientists do not agree about why
there is so much arsenic in the groundwater in Bangladesh. Arsenic naturally
existed in the groundwater before. But some say it was made worse when big
farms drew so much water for irrigation that they changed the flow of the
water underground and made the arsenic concentrate (get stronger).
About 40,000 people in Bangladesh are now sick from arsenic poisoning,
mostly women, poor people, and domestic workers. Arsenic-related health
problems take years to develop, so many more people will become sick. Better
water is the only way to treat the health problems from too much arsenic.
This disaster got worse for so long, and remained without much study or
remedy, because the people suffering are among the world’s poorest. If water
in the capitol city of Dhaka was contaminated (it is not) or the sickness was
happening in a wealthy country, action would have happened more quickly.
The poisoning in Bangladesh shows the dangers of polluting water. It also
shows the importance of testing water sources and acting quickly if there is
any doubt about water safety.
To remove arsenic from drinking water
A simple filter has been developed in Bangladesh that uses iron nails to take
arsenic out of the water (see page 97 and Resources). This reduces the number
of poisonings, but it does not solve the problem of contaminated water.
A Community Guide to Environmental Health 2012