Kolkata: All of Kolkata, India’s third-largest city by population, is at risk of arsenic contamination if the current level of groundwater depletion continues, admit bureaucrats at the city’s municipal corporation.
“We are very anxious,” says Alapan Bandopadhyay, the commissioner of the Kolkata Municipal Corporation (KMC), admitting that the situation is “grim”.
Source of life: People draw water from a tube well at Baghajatin, Kolkata. According to a study, 77 of the 141 wards in the city have “high levels” of arsenic in groundwater and scientists say prolonged water depletion increases the risk of arsenic contamination. (Photo: Indranil Bhoumik/ Mint)
After having surfaced in 13 of West Bengal’s 18 districts, the toxic metalloid—an element with properties that fall between metals and non-metals—now threatens to wreak havoc in the state’s capital city as well.
Of the 141 wards that the city is divided into, as many as 77 have “high levels” of arsenic in groundwater, shows a study by the School of Environmental Studies (SOES) of Jadavpur University.
In 32 of these 77 wards, the arsenic level is “dangerously high”, and traces of the deadly metalloid were found in samples drawn from 32 more wards, but the level was within permissible limits.
Chronic arsenic poisoning, which stems from long-term exposure through drinking water, could cause a wide variety of diseases, including cancer of the skin, lungs, kidney and urinary bladder. Cancer, though, is a late phenomenon and usually takes more than 10 years to develop, according to the World Health Organization (WHO).
In West Bengal, long-term arsenic poisoning has typically resulted in skin lesions, neurological problems, pre-natal deaths and, in many cases, gangrene leading to amputation, says Dipankar Chakr- aborti, director of research at SOES. He claims almost 15 million people across the state are arsenic-threatened.
Mint was unable to ascertain the number of people, out of Kolkata’s estimated population of 14.7 million, who live in the 77 wards with high levels of arsenic in groundwater.
According to SOES, Howrah, Hooghly, South and North 24 Parganas are among the worst affected districts. In North 24 Parganas, for instance, 29.5% of 54,368 water samples tested by SOES showed “dangerously high level” of arsenic content, and 53.4%, higher than internationally accepted permissible limit. The figures for South 24 Parganas are slightly better, yet pretty alarming: 28.3% of samples showed arsenic content above the WHO-mandated maximum permissible level of 50µg/L (microgram per litre) and 42%, above 10µg/L.
Until recently, arsenic was seen as a threat only in the districts neighbouring Kolkata. But, now, tests show even upscale residential areas in south Kolkata aren’t safe.