Why invite arsenic?

Why invite arsenic?

Arsenic in groundwater is becoming a difficult problem in many parts of the country. Many blame Jal Nigam officials and the public engineering department for the malaise. But this is quite akin to finding convenient scapegoats when the problem is actually quite complex. The point is people need groundwater: both for drinking and for irrigation purposes.

Take the case of West Bengal. In 1959, minor-irrigation projects were started in the state in collaboration with the Exploratory Tubewell Organization of the Union government. As per the 2001 census, there are about 5, 50,000- tube wells in the state; 64 per cent of 54,640 square kilometres of cultivable land in the state is under irrigation by tubewells that tap groundwater. Irrigated farming has supported millions of people, but it has also had a horrible spin off: arsenic levels have risen in the shallow aquifers of West Bengal.

But how did irrigation cause such pollution? The rot set in because water used for farming had high levels of arsenic and the chemical accumulated in the roots of rice plants -- in some cases, the levels were reported to be as high as 169 parts per million. When these roots were ploughed back into the soil, arsenic released from them after getting washed off by irrigation water. The chemical then found its way to the shallow aquifers of West Bengal. This development began a couple of decades back and is continuing unabated. Groundwater irrigation was envisaged as a panacea for food shortage, it has polluted drinking water and killed many.

And this is not all. Preliminary studies indicate that the scourge is fast spreading to parts of Northeast India.
What can be done There are several technologies to remove arsenic from drinking water -- some of these are reverse osmosis, precipitation and flocculation and solar oxidation. But these are costly and unfeasible for rural parts of the country.

Providing safe drinking water to rural communities in fact, requires engaging skills of hydrologists, engineers, medical experts and non-governmental organisations. These specialists should be involved in identifying the areas affected by arsenic, and in collecting data about the extent of the problem. Once this is done, the affected basins should be mapped and permanent observation stations identified. This will not only create a good data bank on individual basins but also ensure ready availability of trained personnel who can be consulted to oversee the problem in future.

Tackling the arsenic menace also requires changing people's mindsets. Since the chemical does not affect humans overnight, there is always a tendency to procrastinate on solutions. The state groundwater organisations and public health departments should take the help of grassroots bodies in raising people's awareness in the affected areas.
Over the long-term But all these are short-term solutions. There is no viable long-term panacea except harnessing surface water to mitigate both drinking water and arsenic problems. The large volumes of surface water that gets discharged into the seas every year can easily be used for these purposes. For example, the government of Meghalaya has created an excellent lake to store surface water; this reservoir supplies water to communities in Shillong. Facilities to create such water bodies exist in all the Northeast states. Besides, the entire region has a good water drainage system; interlinking them scientifically could provide water for irrigation as well as for drinking.

But isn't there a microbial problem with surface water sources in many parts of India? There is, but tackling it is far more easier than removing arsenic from water. And what about the political problems with interlinking? Yes, there are problems here. But solving them is much easier than saving millions from arsenic-related diseases. In fact, making the project completely transparent would take care of the political difficulties: the data generated should be made available in the public domain. Academic institutions and state public works departments should collaborate in the project.

D Chandrasekharam is professor, department of earth sciences and head, centre of studies in resources engineering, Indian Institute of Technology, Mumbai 12jav.net12jav.net