GROUNDWATER ARSENIC CONTAMINATION IN WEST BENGALINDIA
West BengalIndias groundwater arsenic contamination in villages was first reported in 1982, and arsenical
skin lesions were first detected in 1983. Twenty-two patients with arsenical skin lesions were known from
five villages in four districts. About 50% of the districts in West BengalIndia reported groundwater arsenic concentration above
50 mg/L. Six million people are drinking arseniccontaminated water above 50 mg/L from 74 police stations/
blocks in 9 arsenic affected districts including a part of Calcutta city inWest Bengal (Fig. 2).
Fig. 2 Map shows the present arsenic affected areas and blocks of West BengalIndia
In 2600 villages/wards, arsenic in groundwater has been found above 50 mg/L. In a preliminary study from 255 villages,
86,000 people were examined and 8500 people have been registered with arsenical skin lesions. Fig. 3 shows
an arsenic patient with severe keratosis.
Fig. 3 Shows an arsenic patient with severe keratosis.
In affected villages, the following skin manifestations and other symptoms of arsenic toxicity were detecteddiffuse melanosis; mucous membrane pigmentation on tongue,
gum, and lips; spotted melanosis; leuco-melanosis; spotted and diffuse keratosis; and dorsal and limb keratosis.
The following non-dermatological complications were also observed in victims suffering from arsenic toxicityweakness and anemia, muscle pain, nonpetting oedema, conjunctival congestion, laryngitis,
myopathy, neurological problem, chronic bronchitis, asthmatic bronchitis, hepatomegaly, splenomegaly, ascitis,
and various types of external and internal cancer. Arsenical skin lesions from nine affected districts of West Bengal affect an estimated 300,000 people.[1] From arsenic-affected areas of West Bengal, over
99,000 water samples from hand tubewells have been analyzed by flow injection hydride generation atomic absorption spectrometry. Fifty-five percent had arsenic concentrations above 10 mg/L and 25% above 50 mg/L.
The highest concentration of arsenic found in a hand tubewell was 3880 mg/L. About 25,000 biological samples (hair, nail, urine, skin scale) have been analyzed from villagers living in arsenic-affected villages (about
40% samples of total 25,000 are from arsenic patients) and on average 80% of the biological samples had arsenic above normal arsenic level in human body. This indicates many more are subclinically affected.
