Arsenic in Bangladesh Drinking Water: Which Districts Are Affected and How to Stay Safe

The Scale of Bangladesh's Arsenic Problem

Bangladesh faces what the World Health Organization has described as the largest mass poisoning of a population in history. Naturally occurring arsenic leaches from geological deposits into shallow groundwater across a vast area of the country. The problem was largely hidden for decades because arsenic has no colour, taste or smell — families drinking heavily contaminated water have no way of knowing without a test.

The scale is staggering. Estimates suggest that between 35 and 77 million people in Bangladesh are exposed to arsenic concentrations above the WHO guideline of 10 micrograms per litre (µg/L). Bangladesh's own national standard is 50 µg/L — five times more permissive than the WHO limit — and many wells exceed even this higher threshold significantly.

Most Affected Districts

Arsenic contamination is concentrated in the alluvial plain districts of southern and central Bangladesh. The following districts have documented high-prevalence arsenic contamination in groundwater:

Districts in the northwest (Rangpur division) and hilly southeast (Chittagong Hill Tracts) generally have lower arsenic levels in groundwater, though local variation exists everywhere.

Health Effects of Chronic Arsenic Exposure

Arsenic poisoning from drinking water is not an acute illness — it develops slowly over years and decades of exposure. The health effects are severe and irreversible once they develop:

Early signs (after 5–10 years of exposure):

• Skin changes — darkening (melanosis), white spots (leucomelanosis), and hardening of skin on palms and feet (keratosis)
• Weakness and fatigue
• Chronic cough

Long-term effects (after 10–20+ years):

• Cancers — skin, bladder, kidney and lung cancers are significantly elevated in arsenic-affected populations
• Peripheral neuropathy — numbness, tingling and weakness in limbs
• Cardiovascular disease — arsenic damages blood vessels and heart muscle
• Liver and kidney disease

Effects on children:

• Impaired cognitive development and lower IQ scores
• Reduced immune function
• Stunted growth and development

Children and pregnant women are the most vulnerable — arsenic crosses the placental barrier and affects foetal development.

How to Test Your Water for Arsenic

A standard TDS meter does not detect arsenic. It measures total dissolved solids, not specific contaminants. To test for arsenic you need one of the following:

1. Field test kit — inexpensive kits (৳500–৳1,500) use chemical reactions to detect arsenic above certain thresholds. They are quick but less accurate than lab tests.
2. Government testing — the Department of Public Health Engineering (DPHE) conducts water testing in affected areas. Contact your local DPHE office for testing.
3. Private laboratory — several labs in Dhaka offer comprehensive water quality analysis including arsenic. Costs range from ৳1,500 to ৳5,000 for a full panel.
4. BRAC and NGO testing programmes — multiple NGOs operating in affected districts offer free or low-cost arsenic testing.

What Removes Arsenic — and What Does Not

This is critical: not all water purifiers remove arsenic. UV purifiers, UF filters and standard carbon filters do not remove dissolved arsenic at all. Only specific technologies remove arsenic effectively:

For household use in arsenic-affected areas, a multi-stage RO purifier is the most practical and reliable solution. Ensure the unit you purchase is tested and certified for arsenic removal — ask specifically for documentation.

Immediate Steps If You Are in an Affected Area

1. Stop drinking unfiltered groundwater immediately — use deep tubewells (below 150 metres) which typically have lower arsenic, or rainwater, or treated municipal supply if available
2. Get your water tested — contact DPHE or use a field test kit before assuming your water is safe
3. Install an RO purifier rated for arsenic removal — verify the specification sheet confirms arsenic rejection
4. Cook with purified water — boiling does not remove arsenic; it concentrates it as water evaporates
5. Check your children first — if children show skin changes, unusual fatigue or developmental concerns, consult a physician and mention arsenic exposure

The arsenic crisis in Bangladesh is preventable at the household level with the right information and the right water purifier. Awareness and a tested RO system are your most important defences.