NEW YORK (Reuters Health) - Clay pots containing filtration
materials are a cheap and effective way to remove dangerous levels of arsenic commonly
found in well water in Bangladesh, according to a new report.
Last year the World Health Organization (WHO) called the situation in Bangladesh
"the largest poisoning of a population in history." WHO estimates that between
35 million and 77 million Bangladeshis are at risk of drinking arsenic-contaminated water.
Arsenic naturally occurs in groundwater as a result of minerals dissolving over time
from rocks and soil.
Lead investigator Ziya Uddin of CARE-Bangladesh in Dhaka presented the results of a
study of the filtration pots last month in Atlanta, Georgia, at the American Public Health
Association's annual meeting.
The filtration system consists of three unglazed clay pots that can hold 15 liters of
water, stacked one above the other. The top two pitchers contain filtering material
consisting of sand, iron chips, brick nuggets and charcoal. The bottom pitcher collects
the filtered water, which is then used for drinking and cooking.
In the study, the researchers placed 20 pitcher systems in homes in 3 arsenic-affected
villages in northern Bangladesh. Arsenic levels were tested in the filtered water each
month for two months and compared to arsenic levels in the well water source.
Uddin and colleagues report that, on average, the water filtration system removed 95%
of the arsenic.
While many of the users said they were happy with the taste of the water, many also
noted that they were able to filter only 25 to 28 liters of water per day with the system.
This was not enough for cooking and drinking for a family of 8 to 10, Uddin reports.
The researchers note that bigger clay pitchers can be used for bigger families and that
more than one filtering system can be used in a household.
The cost of the filtration system used in this study was approximately US $6.10.
Materials used to make it are readily available in most villages, the authors note.
The first signs of arsenic poisoning appeared in Bangladesh the early 1980s, when
people began developing symptoms associated with arsenic poisoning including painful skin
lesions on the hands and feet and skin pigmentation changes on the upper chest, arms and
Exposure to arsenic at high levels poses serious health effects, as it is a known human
carcinogen and can increase the risk of skin, bladder and lung cancer. In addition, it can
affect the vascular system in humans and has been associated with the development of
diabetes. The effects of arsenic poisoning may not show up until about 10 years after
Arsenic contamination has been identified in many nations of the world including the
United States. Food and water are the major sources of arsenic exposure for US citizens,
according to the Environmental Protection Agency.