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close this bookContamination of Drinking-Water by Arsenic in Bangladesh: A Public Health Emergency (WHO, 2000, 16 p.)
close this folderLong-term health effects of exposure
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View the documentSkin lesions
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Skin lesions

The latency for arsenic-caused skin lesions (i.e., the time from first exposure to manifestation of disease), in particular keratoses, is typically about 10 years (22). In the 1997 consultancy, it was found that the youngest individuals with skin lesions caused by arsenic were about 10 years old. Other studies have shown that skin lesions also occur in children younger than 10 years (23). It was also found that in adults, exposures commenced approximately 10 years before they stated the skin lesions began to appear. In some instances, the apparent latency for the appearance of skin lesions from the time of first exposure to contaminated water from the tube-well currently in use was much shorter, but as no measurements were available for water from previously used tube-wells, a short latency from first exposure could not be inferred. However, latency that is shorter or longer than 10 years may occur, and the rapidity of the appearance of skin lesions appears to be dose dependent (22). Further studies of the latency and patterns of occurrence of skin lesions are needed and these will require careful interviewing of participants about their current and past exposures.

Box 1. Magnitude of arsenic poisoning in Bangladesh

Population of Bangladesh:

125 million

Total population in regions where some wells are known to be contaminated:

35–77 million

Maximum concentration of arsenic permitted in drinking-water according to WHO recommendations:

10 µg/l

Maximum concentration allowed in Bangladesh:

50 µg/l (similar to many countries worldwide)

Number of tube-wells sampled by the British Geological Survey (1998):


– Proportion of wells with arsenic concentrations >50 µg/l:


– Proportion of wells with arsenic concentrations >300 µg/l:


Box 2. Long-term health effects of exposure to arsenic

Skin lesions
Skin cancer
Internal cancers


Neurological effects
Hypertension and cardiovascular disease
Pulmonary disease
Peripheral vascular disease
Diabetes mellitus