Arsenic in Asia

Arsenic contamination of drinking water is a global problem, but nowhere is the problem more severe than in Bangladesh and West Bengal, India, where over 112 million reside in areas where groundwater concentrations exceed the World Health Organization's (WHO) maximum permissible level of 50 micrograms per liter (pg/L) and its lower recommended concentration of 10 pg/L. Arsenic exposure is associated with health effects such as skin lesions and lung, liver, and bladder cancers. In this issue, Uttam K. Chowdhury and other researchers from the School of Environmental Studies at Jadavpur University in Calcutta join with colleagues from the Dhaka Community Hospital Trust in Bangladesh and the Calcutta Medical College and Hospital to report their findings that arsenic contamination of drinking water is more severe in Bangladesh than in West Bengal, but that some of the preliminary health effects associated with arsenic-contaminated water can be reversed with a healthy diet and uncontaminated water [EHP 108:393-397]. Forty-two districts in Bangladesh, with a population of 79.9 million , have groundwater with arsenic concentrations in excess of 50 pg/L. Nine districts in West Bengal, with a population of 42.7 million , have concentrations in excess of the WHO's maximum permissible level. Over 90% of the residents in Bangladesh and West Bengal use groundwater for drinking and cooking. To determine the extent of drinking water contamination, the researchers collected nearly 11,000 water samples over a four-year period from districts in Bangladesh and discovered that 59% of those samples exceeded 50 pg/L. Of 58,166 samples from West Bengal, 34% exceeded 50 jig/L. The levels of contamination also run higher in Bangladesh. Of the samples from Bangladesh exceeding the WHO maximum permissible level, nearly one-quarter were contaminated with concentrations of 100-299 pg/L. Nearly 11% of the samples contained concentrations of 300-499 pg/L, while 8.7% contained concentrations of 500-1,000 p pg/L. Only 14% of the samples from West 7 Bengal contained 100-299 pg/L, and only 3.9% had concentrations of 300-1,000 pg/L. Similarly, the researchers found that a higher percentage of villagers in Bangladesh suffer from skin lesions than in West Bengal. Nearly one-quarter of the 11,000 villagers surveyed in Bangladesh suffered skin lesions, compared to slightly more than 15% of the 29,000 villagers surveyed in West Bengal. During 10 years of field surveys in West Bengal and 5 years in Bangladesh, the researchers observed that concentrations in excess of 300 pg/L were associated with arsenical lesions, although lesions …