Blue Water Series - Health Issues - Article 3

Then a damp gust

Bringing rain

Ganga was sunken, and the limp leaves

Waited for rain, while the black clouds

Gathered far distant, over Himavant.

The jungle crouched, humped in silence.

Then spoke the thunder…..

                                                                                                                                                                                                                                                    The Waste Land, T.S.Elliot

Parul Bala Nag, aged 85, is a thin and small woman who curses her own longevity. Living her entire life in Merudandi Village, Basirhat, North 24 Parganas District of West Bengal, she endured the experience of witnessing death of 5 members of her family in last 10 years including her two sons and a daughter. To her experience, they were all taken by devil himself, his signs manifest as black spots on skin in the bodies of all deceased members, then open lesions and finally vomiting until death relieved them of their misery. She heard people talking about the devil, so she knew his name. The devil was called Arsenic. On a fateful day of 2009, she was waiting for the news of the medical report of her only grandson to arrive from the city. To her horror the young man had developed those dreaded dark spots on his back couple of months ago…

Bangladesh is not the only Arsenic hit place, the attached Indian state of West Bengal, my native state, shares the same curse. In a twisted irony of fate, the sparkling clear water that nourishes life elsewhere, takes life here on an unprecedented scale. Here is a video news clip.

Officially, arsenic poisoning in West Bengal was first diagnosed by a dermatologist K.C. Saha of School of Tropical Medicine (STM), Calcutta (Kolkata was previously known as Calcutta) to an outdoor patient of village Ramnagar of Baruipur police station in the district of South 24-Parganas on 6th July, 1983. Later it came out that many arsenic patients existed in many villages well before 1983 but they could not be clinically diagnosed, so were not highlighted. Garai et al. reported the first scientific paper published on Arsenic toxicity in West Bengal where he had warned of malignancy of the hyperkeratotic spots and liver if diagnosis is delayed. The School of Environmental Studies (SOES), Jadavpur University joined the arsenic work at the beginning of 1988. As for the present situation, I am a bit more thorough than the reporter of the news clip, so I shall give a map below.

[Map Credit: soesju.org]

The scale of the problem can be easily understood from the number of affected population. See the table below (figures updated till 2001).

[Source: Arsenic Pollution in West Bengal by Dr. D. Elangovan & M.L.Chaklah]

The tragic and scary situation of Arsenic contamination of ground water in large parts of West Bengal and Bangladesh has a strange geogenic spin. I call it strange because 1. If it is geogenic in nature, it is not clear why it never emerged as a mass killer before and 2. Arsenic is just a heavy metal; it is not so much of a poison and was even traditionally considered medicinal. It becomes toxic only when its concentration in aqueous medium crosses a threshold value. Lead and Fluorides exhibit same properties. So I have a feeling that despite As-contamination being geogenic in nature its recent life threatening effects, logically, requires a vector of a recent origin. I suspect that vector to be anthropogenic. I shall come back to it later.

This argument of mine is risky. Arsenic poisoning through ground water contamination is academically attributed to geological nature of sub-soil formations, the chemistry of Arsenic sulfides, sulphosalts and Arsenopyrites, the physico-chemical process of Arsenic release into ground waters to reduction of Arsenopyrites releasing Arsenic to contaminate the ground water. A kind of bacterial activity is believed to be helping such reduction. None of this has anything to do with human activity.

Or is it?

Here is my case. During the eighties there was a remarkable change in the minor irrigation sector due to rapid growth in Agro-commercialization. Cultivation of Summer Paddy (Boro) ” expanded in the seven districts of South Bengal with an unpredictable rate each year. The Boro cropping is almost dependent on the tube-well irrigation. The later HYV (High Yield Variety) paddy that became commercially popular demanded huge quantities of water which public surface water irrigation projects failed to meet, hence more ground water extraction took place. Immediate manifestation of that agro practice was lowering of ground water level at alarming rate. The ground water occurring mainly within the shallow zone (20-60m below ground level) is characterized by high arsenic (>0.5 to 1 or above mg/l) and the principal source of arsenic is the arsenic sulphides minerals deposited along with clay, peat, with iron in the reducing environment. The lowering of groundwater at rapid rate during summer season causes aeration of aquifer oxidizing the arsenic sulphides, which makes it water soluble. It percolates from the subsoil into water table during monsoon. Sounds anthropogenic, doesn’t it?

I am not the only one skeptical about human related causes of Arsenic contamination or at least an important vector that aggravated the situation. But I am one of very few. A notable one is Dr. Dipankar Chakrabartyi, from School of Environmental Studies, Jadavpur University (my Alma Mater). Chakraborti brought the crisis to international attention in 1995. Beginning his investigation in West Bengal in 1988, he eventually published, in 2000, the results of a study conducted in Bangladesh, which involved the analysis of thousands of water samples as well as hair, nail and urine samples. They found 900 villages with arsenic above the government limit.

Chakraborti has criticized aid agencies, saying that they denied the problem during the 1990s while millions of tube wells were sunk. The aid agencies later hired foreign experts, who recommended treatment plants which were not appropriate to the conditions, were regularly breaking down, or were not removing the arsenic.

Chakraborti says that the arsenic situation in Bangladesh and West Bengal is due to negligence. He also adds that in West Bengal water is mostly supplied from rivers. Groundwater comes from deep tubewells, which are few in number in the state. Because of the low quantity of deep tubewells, the risk of arsenic patients in West Bengal is comparatively less.

According to the World Health Organisation, “In Bangladesh, West Bengal (India) and some other areas, most drinking-water used to be collected from open dug wells and ponds with little or no arsenic, but with contaminated water transmitting diseases such as diarrhoea, dysentery, typhoid, cholera and hepatitis. Programmes to provide ‘safe’ drinking-water over the past 30 years have helped to control these diseases, but in some areas they have had the unexpected side-effect of exposing the population to another health problem—arsenic.” The acceptable level as defined by WHO for maximum concentrations of arsenic in safe drinking water is 0.01 mg/L. The Bangladesh government's standard is at a slightly higher rate, at 0.05 mg/L being considered safe. WHO has defined the areas under threat: Seven of the nineteen districts of West Bengal have been reported to have ground water arsenic concentrations above 0.05 mg/L. The total population in these seven districts is over 34 million, with the number using arsenic-rich water is more than 1 million (above 0.05 mg/L). That number increases to 1.3 million when the concentration is above 0.01 mg/L. According to a British Geological Survey study in 1998 on shallow tube-wells in 61 of the 64 districts in Bangladesh, 46% of the samples were above 0.01 mg/L and 27% were above 0.050 mg/L. When combined with the estimated 1999 population, it was estimated that the number of people exposed to arsenic concentrations above 0.05 mg/L is 28-35 million and the number of those exposed to more than 0.01 mg/L is 46-57 million (BGS, 2000).[14]

Throughout Bangladesh, as tube wells get tested for concentrations of arsenic, ones which are found to have arsenic concentrations over the amount considered safe are painted red to warn residents that the water is not safe to drink.

The solution, according to Chakraborti, is “By using surface water and instituting effective withdrawal regulation. West Bengal and Bangladesh are flooded with surface water. We should first regulate proper watershed management. Treat and use available surface water, rain-water and others. The way we're doing at present is not advisable.”

I do not think the reasons suggested by Chakrabarti are anything to do with geogenicity of Arsenic in West Bengal or Bangladesh.

In any case, this is not a problem only limited to Bangladesh and West Bengal, India. See picture below.

I wish people from each affected area report on the As-contamination issues and check if they see any human related vector aggravating the problem.

On a note of hope, a very innovative and cost effective Arsenic removal technology has been devised in Jadavpur University again by Dr. Bhaskar Sengupta and his team of colleagues, which is now famous as Subterranean Arsenic Treatment. In subterranean arsenic removal (SAR), aerated groundwater is recharged back into the aquifer to create an oxidation zone which can coprecipitate iron and arsenic. The oxidation zone created by aerated water boosts the activity of the arsenic-oxidizing microorganisms which can oxidize arsenic from +3 to +5 state SAR Technology. No chemicals are used and almost no sludge is produced during operational stage since iron and arsenic are trapped under the earth. Thus toxic waste disposal and the risk of its future mobilization is prevented by this technology. Also, it has very long operational life similar to the long lasting tube wells drawing water from the shallow aquifers. The Subterranean Arsenic Treatment (SAR) technology will soon be used in America where Dr Sen Gupta is setting up a treatment plant near Bellingham in the State of Washington.

Effective implementation of this remedy is, on large part, dependent upon the sincerity of the Local Governments.

[Feature Image Credit: Environmentalchristian]