Flouride, arsenic and nitrate in water
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Those who depend on groundwater have to check it for physical, chemical and biological components
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Groundwater in a natural condition accumulates over time, seeping down through the soil and naturally cleansing and filtering itself. In the absence of sunlight, bacteria too lessens and in general groundwater in the deeper aquifers can be of the highest quality.
However, in its process of downward migration and due to human activities, pollution of groundwater is on the rise.
Natural chemical pollutants include fluoride and arsenic and man-made pollutants include nitrates .
One of the naturally occurring components of groundwater in some places is fluoride. In India, 17 States report fluoride in groundwater in parts of their area and 66 million people are reported at risk.
A naturally occurring mineral, various strata of rocks contain fluoride and this leaches into groundwater in its passage through such strata.
While a certain amount of fluoride is believed to strengthen bones and teeth, in excess of 1.5 parts per million it can lead to dental fluorosis and in even higher doses can cause skeletal fluorosis.
Nitrate in groundwater has fertilizers as a major source in rural areas but waste from septic tanks, leaking sewage pipes and pit latrines are the major cause of nitrate contamination in urban areas.
Nitrates impact infants and the elderly and impair respiratory systems. When nitrate-containing water is imbibed, the stomach can convert it to nitrites which are then absorbed in the bloodstream.
These nitrites inhibit the transport of oxygen, causing shortness of breath and heart attacks.
Sending groundwater which is consumed to a recognised laboratory for testing would give a good indication whether it is fit for consumption or not. The presence of fluoride, arsenic and nitrates within limits or exceeding it would quickly establish the treatment process that is required.
Treatment
Specific treatments are available for each of these minerals if found in excess.
In general, however, a reverse osmosis plant will eliminate all three. Ion exchange systems can remove fluoride from groundwater.
Ordinary candle filters and UV treatment systems will not remove fluoride, arsenic or nitrates.
Since rural areas depend largely on groundwater as their source of drinking water, occurrence of fluoride can cause severe health problems.
A good, balanced diet is also a fluoride inhibitor but poverty and malnutrition results in a more severe impact in rural areas. Treatment systems such as reverse osmosis cannot be afforded by most of the rural population.
In such a case, systems such as rooftop rainwater harvesting can be a boon. Harvested rainwater is free from fluoride, nitrates and arsenic. From a clean catchment such as a roof, the water can be collected and conveyed through good filters to remove physical contaminants.
It can be stored in underground tanks of 5,000 to 8,000 litres.
This water, if kept free from contamination, can last years. Since the impact of chemicals comes from ingestion through drinking and cooking, harvested rainwater can be used for drink0ing and cooking.
At the rate of 20 litres per family per day, the annual demand is around 7,300 litres, easily harvestable by even the smallest household.
A project of the Government of Karnataka called ‘Sachetana’ does exactly that in 64 villages. Being implemented by the NGO BIRD-K, families build their own rainwater collection systems and manage it.
Rainwater harvesting can also provide safe drinking water in urban areas not supplied by piped water systems and where groundwater is polluted.
It is time to use the rain effectively. That is water wisdom.
www.rainwaterclub.org
zenrainman@gmail.com 080-23641690
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