1.
ARSENIC - A NATURAL THREAT
FOR BANGLADESH

2.
Background
Bangladesh's arsenic contamination of water was the world's worst mass poisoning.
43,000 people died because of arsenic poisoning every year in Bangladesh (WHO-2012)
Annual report (Y19-20)- DPHE, says the presence of arsenic in tube-wells in 61 out of 64 districts.
• Worst affected districts :
• CHANDPUR (90%), MUNSHIGANJ (83%), GOPALGANJ (79%),
• MADARIPUR (69%), NOAKHALI (69%), SATKHIRA (67%),
• COMILLA (65%), FARIDPUR (65%), SHARIATPUR (65%),
• MEHERPUR (60%) and BAGERHAT (60%).
• Sources: Toxic Arsenic (As) can naturally occur at high levels in soil & rocks.
Drilling into aquifers can release As into drinking water supplies.
• Other sources: Mining, metal processing, geothermal
• Data from random national survey using field kits by DPHE/UNICEF
• http://en.banglapedia.org/index.php/Arsenic

3.
Causes of Arsenic Contamination in Bangladesh
Oxidation of Arsenic Pyrites or Ferrous Hydroxides Hypothesis
Arsenic pyrites or ferrous hydroxides are very arsenic rich minerals
which oxidized and arsenic is released from the minerals. The origin
of arsenic rich groundwater is man-made. The whole processes also
accelerate by different geological process like weathering, erosion,
sedimentation, use of irrigation and fertilizers.
Oxy-hydroxide Reduction Hypothesis
Arsenic is assumed to be present in alluvial sediments
with high concentrations in sand grains as a coating of
iron hydroxide and releases arsenic into groundwater.
The origin of arsenic rich groundwater is due to a
natural process and has been present for thousands
of years without being flushed from the delta.

4.
Impact on Public Health
Undetectable in its early stages, arsenic poisoning takes between 8 and 14 years to impact on health,
depending on the amount of arsenic ingested, nutritional status, and immune response of the individual.
Observable symptom to the arsenic poisoning:
Thickening and discoloration of skin, stomach pain, nausea,
vomiting, diarrhea, numbness in hand and feet,
partial paralysis, blindness etc.
Health effects:
Short term, hi dose – poison, organ failure
Long term, low dose– increases risk for cancers of the bladder,
lung, kidney, liver, colon, and prostate; nerve damage;
non-neoplastic diseases, including cardiac disease,
cerebrovascular disease, pulmonary disease,
diabetes mellitus and diseases of the arteries,
arterioles, and capillaries.

5.
Mitigation Option
A number of techniques have been used by government of Bangladesh,
international and non-government agencies for mitigating the problem:
• Household level arsenic removal: The available techniques
include 3-kalsi method, safi filter, SOES-filter, 2-bucket system,
passive sedimentation, etc.
• Very shallow tube-wells and dug-wells
• Pond sand filter
• Rainwater harvesting
• Deep groundwater
• Treated surface water
• Arsenic removal plant
Most common techniques for removal of arsenic from water are:
Oxidation, coagulation, filtration, adsorption,
ion exchange and membrane filtration (reverse osmosis)
The most commonly used arsenic removal units are:
Fill and Draw Units, BUET Activated Alumina Unit,
BUET Iron Coated Sand Unit, BCSIR Filter Unit,
Bucket Treatment Unit (BTU), MRT-1000 an Reid System Ltd (TW),
Stevens Institute Technology Unit.