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Contamination Of Contaminating Groundwater In Assam Remains A Silent Issue

"Climatic changes, like erratic rainfall which results in sudden long, dry spells, leads to less runoff water seeping into the ground and rejuvenating the water table. This results in increase in concentration of minerals like fluoride, that is pumped up by borewells."

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"When dilution of aquifers is low (because of erratic rainfall), the concentration (of minerals like fluoride) goes up," he said. And although Assam gets a good amount of rainfall, "the water table has depleted in some places". Pixabay

It’s peak election season. But, even as political parties go all out to appease voters, the worsening quality of groundwater hardly finds any mention.

In northeast India, Assam is in the middle of a grave groundwater contamination crisis. According to government estimates, fluoride contamination affects 23 districts and arsenic contamination affects 24 districts (out of a total 33) in the state. Even as people grapple to survive this basic necessity of life – excess fluoride can lead to dental and skeletal fluorosis, and arsenic is known to cause cancer – experts warn of a worsening situation in the future.

Understanding the root of a crisis is essential to finding its pragmatic solution, and in this context, Dr Manish Kumar, faculty at Discipline of Earth Science in IIT Gandhinagar, compared the situation to a glass of water in which spoonfuls of sugar are added. Until the water is saturated, it will keep dissolving the sugar, and then, the granules would start settling without further dissolution.

Likewise, minerals containing fluoride and arsenic found naturally in rocks of underground aquifers will dissolve more and leach more fluoride and arsenic under unsaturated conditions. Aquifers essentially constitute rocks and water, surrounded by microbes and organic matter.

“Any kind of anthropogenic stress on aquifers, like pumping, irrigation and return flow, leads to change in the saturation condition of groundwater and thereby enhances the release of arsenic (and fluoride) into the water,” Dr Kumar told this correspondent. Through extensive research on spatial distribution of geogenic contaminants across the Brahmaputra river, Dr Kumar and his team found the co-existence of arsenic, fluoride and uranium at some places.

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Likewise, minerals containing fluoride and arsenic found naturally in rocks of underground aquifers will dissolve more and leach more fluoride and arsenic under unsaturated conditions. Aquifers essentially constitute rocks and water, surrounded by microbes and organic matter. Pixabay

“We also found several places in Assam where the water is not yet saturated with arsenic and fluoride bearing minerals and thus prone to higher arsenic and fluoride concentration in their aquifers,” he said. In Nagaon district, for example, about 60 per cent of the samples tested were found to have “unsaturated” water.

Climatic factors like erratic rainfall, recharge and runoff also play a role in governing the weathering of minerals – otherwise found naturally – in groundwater, Dr Kumar said. The draft report of the Assam State Action Plan on Climate Change (2015-2020) states that Assam has been facing “continued warming of atmosphere” and “erratic rainfall” as a result of which there have been erratic flood and drought conditions since 2003.

Dr Robin Kumar Dutta, professor in the Chemical Sciences department of the Tezpur University, concurred with the linkage between climatic change and groundwater contamination.

“When dilution of aquifers is low (because of erratic rainfall), the concentration (of minerals like fluoride) goes up,” he said. And although Assam gets a good amount of rainfall, “the water table has depleted in some places”.

The issue, Dr Dutta added, also needs to be examined through the lens of geomorphology. “Karbi Anglong and Hojai, for example, fall in the rain shadow area and are among the fluoride-affected places in Assam,” he said. Dr Dutta has designed a low-cost filter technology to remove fluoride and arsenic (and iron) from water, which he has patented.

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ven as people grapple to survive this basic necessity of life – excess fluoride can lead to dental and skeletal fluorosis, and arsenic is known to cause cancer – experts warn of a worsening situation in the future.
VOA

Geomorphology, added activist Dharani Saikia, is why, at times, adjoining villages can have completely different results when their water is tested for fluoride (or arsenic) contamination. Working on the issue of fluoride contamination for many years now, particularly in the Nagaon and Hojai districts – two of the worst-affected in Assam – he stated the example of the Tapatjuri village.

“Tapatjuri in the Hojai district is one of the worst affected by fluoride contamination of groundwater. Any child you see here has stained teeth – the sign of dental fluorosis – and some have bent legs (skeletal fluorosis). In contrast, its nearby villages have no problem of fluoride contamination,” he explained.

“Climatic changes, like erratic rainfall which results in sudden long, dry spells, leads to less runoff water seeping into the ground and rejuvenating the water table. This results in increase in concentration of minerals like fluoride, that is pumped up by borewells,” Saikia further said.

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It is, however, not a hopeless situation and the key lies in revisiting and fine-tuning traditional methods. For instance, in Tapatjuri, the Public Health and Education Department (PHED) has put red-crosses on hand-pumps, indicating contamination. The villagers are now dependent on the PHED water supply from nearby rivers. (IANS)

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India: Major Work on Mapping Fast Depleting Groundwater Reserves is On

The data would be useful in formulating policy regarding groundwater reserves and to utilise it carefully

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The government has launched mapping of the groundwater reserves of the 24 lakh sqkm of mappable area, of which 10 lakh sqkm has been mapped. Pixabay

With water fast becoming a stressed resource and the Narendra Modi government focusing majorly on water conservation and accessibility — as part of ‘Har Ghar Jal to provide water to every household, a major work on mapping the fast depleting groundwater reserves is on across the country.

India has 447 billion cubic metres of replenishable groundwater reserves, of which 60-70 per cent goes off in irrigation.

The government has launched mapping of the groundwater reserves of the 24 lakh sqkm of mappable area, of which 10 lakh sqkm has been mapped, and the rest will be completed over the next year or so.

The data would be useful in formulating policy regarding groundwater reserves and to utilise it carefully.

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With water fast becoming a stressed resource and the Narendra Modi government focusing majorly on water conservation and accessibility. Pixabay

Despite having major dams, the dependence on groundwater has continued over the years. The following data says it all: Around 85 per cent of irrigation needs is met by groundwater; 80 per cent of rural drinking water needs is met by groundwater while 55 per cent of the urban drinking water source is groundwater.

While depletion of surface water is visible, in the form of shrinking or drying up water bodies like ponds and rivers, in the case of groundwater it is invisible as it is deep underground. But it is not an infinite source of water, and its replenishment is slow.

Groundwater is a precious resource and the challenges of its fast depletion are being tackled by the government under the new Jal Shakti Ministry — the merged entity comprising the earlier Drinking Water and Sanitation, and the Water Resources and Ganga Rejuvenation ministries.

India’s per capita availability of water is 1,400 cubic metres per year, while it gets 4,000 billion cubic metres in the form of precipitation, like rain and snow.

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With most of the rainfall flowing off, the focus would now be on how to best utilise the water resources, through localised rain water harvesting in cities and homes.

As part of the water conservation efforts, Prime Minister Modi had written to over 2 lakh village heads (sarpanches) last month to conserve rainwater during the monsoon. The letters were hand delivered to each sarpanch.

While the water availability presents an alarming picture, there are many good initiatives taking place across the country and could be learning points. In Rajasthan, the traditional form of rainwater harvesting, of building storage tanks under the house, called ‘tanka’, are very effective in conserving water.

Among other measures would be to improve the water use efficiency of dams, as most of the water used in farming through dams is lost through leakages and evaporation.

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India has 447 billion cubic metres of replenishable groundwater reserves, of which 60-70 per cent goes off in irrigation. Pixabay

Another factor to be considered is that water-guzzling crops like paddy, wheat and sugarcane use up 80 per cent of the irrigation water, which means that the other crops like millets are able to survive on little water. But to make farmers diversify from paddy and wheat to millets would not be easy and for this many other factors, like people’s choice, the market etc, would have to be taken into consideration.

Micro-irrigation and drip-irrigation and recycling water are other measures that would receive focus.

Using recycled sewage water for use in industries is another important step. Last year, the Indian Oil Corporation in Mathura inked an agreement to utilise recycled sewage water for use.

Recycled sewage water could also be used for domestic purposes like watering lawns, car washing and cleaning.

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As water is a state subject, the central government provides states with the technical know-how and financial help in managing water resources. Many states have set up bodies for conserving water, like Rajasthan’s ‘Mukhya Mantri Jal Swavlamban Abhiyan’, Maharashtra’s ‘Jalyukt Shivar Abhiyaan’ to make the state drought-free, Telanagana’s ‘Mission Kakatiya’, ‘Neeru-Chettu’ in Andhra Pradesh and ‘Sujalam Sufalam Abhiyan’ in Gujarat.

The Government of India also provides funds to states for water conservation/water harvesting through the MNREGA (Mahatma Gandhi National Rural Employment Guarantee Act), with Rs 60,000 crore being made available annually.

The government last week launched a campaign for water conservation and water security to focus on 1,592 “water stressed blocks” across 256 districts.

As part of the push, senior officials have been deployed across the country to assess ongoing schemes and plan ways to conserve water. They would also focus on Behaviour Change Communication to convince people to conserve water, and make it into a habit.

“Water conservation is planned to become like a Jan Andolan, or mass movement, with peoples’ participation. Following the Prime Minister’s directive, it has been taken up in mission mode,” Akhil Kumar, Joint Secretary Ministry of Water Resources told IANS. (IANS)