Fluoride Pollution

Fluoride is often called a two edged sword. In small doses it has remarkable influence on the dental system by inhibiting dental caries, while in higher doses, it causes dental and skeletal fluoresis. In India 62 million people including 6 million children are affected with fluoride related health diseases. Excess fluoride in ground water is reported from 17 States, which include Andhra Pradesh, Rajasthan, Karnataka, Maharashtra, Tamil Nadu, Madhya Pradesh, Uttar Pradesh, Jammu and Kashmir, Punjab, Kerala, Orissa, Bihar, Gujarat. Of which Uttar Pradesh, Rajasthan, Gujarat, Andhra Pradesh and Tamilnadu are severely affected. As per water technology mission, 25 million people residing in 8700 villages in India are affected by fluoresis. Concentration level of fluoride in India reported from groundwater varies from 0.5 to 50 mg/l. Fluoride concentration has significant positive relationship with pH and negative relationship with hardness and magnesium.

The major factors of high fluoride anomaly in India include wide spread occurrence of fluoride rich soil, excessive use of phosphatic fertilizer, indiscriminate disposal of industrial effluent from phosphatic fertilizer, mining (Cu, Fe) and allied industries.

Fluoride levels in (ground) water can be reduced with addition of calcium hydroxide at pH about 10 . The NALGONDA technique is considered to be the most tried and cost effective technique of fluoride removal, however it also requires second stage treatment.

Arsenic Pollution

In India, arsenic pollution in groundwater is mainly reported from West Bengal. Since its first reported case in early eighties, there are 1312 affected villages, 15 non-municipal and 9 municipalities in 8 districts in the State till date. On an approximation 34000 sq km area in the State is reported with high concentration of arsenic in drinking water abstracted from tubewells. Number of people at risk and other specific details are appended in table …. Some of the most affected districts in the State are South 24 Pargana ( conc.0.06-3.20 ppm), North 24 Parganas (conc 0.06-1.28 ppm), Malda (conc 0.05-1.434 ppm), Nadia (conc 0.05-1.0 ppm), Murshidabad (conc 0.05-0.90 ppm) and Bardhaman (conc 0.10-0.50 ppm), Howrah(conc 0.09 ppm) and Hooghly (conc 0.6 ppm). The pollution is mostly reported from the intermediate water depth of 20-80 meter below ground level. The arsenic anomaly in the State is associated with high iron, calcium, magnesium and bicarbonates with low sulphate, fluoride and chloride. The problem of arsenic pollution has been reported to be due to the geological formations of the source material. Occurrence of ' arseno-pyrite' and the change of geo-chemical environment due to over-exploitation of groundwater or excessive fluctuation of groundwater table.

Nitrate Pollution

The problem of nitrate pollution in groundwater becomes severe in the country. The state of Maharashtra alone showed severe problem of nitrate pollution. The studies carried-out by Central Ground Water Board in the State revealed that, out of 688 samples, 75 % sample as have shown nitrate levels below desirable limits, while 14 % samples have nitrate levels above 100 mg/l. While the districts Bhandara, Nagpur and Pune have shown the nitrate concentration having above 45 mg/l., the Jalna district contributes highest percentage ( 55.56 %) of nitrate content above permissible limit. Other districts like Akola, Amravati, Chandrapur, Jalana, Sholapur, Wardha,Yavatmal have shown nitrate concentration exceeding 100 mg/l.

Indiscriminate Disposal of Sewage and Garbage

With increasing urbanization, the groundwater pollution due to indiscriminate disposal of untreated sewage and garbage has also acquired alarming proportion. With 70 -80 % of water supply getting converted into wastewater and limited facility ( 26 %) for its treatment, further compound the problem as encountered in all the major cities in India. This has resulted into outbreak of water borne diseases apart from microbial contamination of groundwater.

Fig 15 : Status of inland salinity in different affected States
Salt Water Intrusion

Salt Water Intrusion

Along about 7000 km long Indian coast line coastal aquifers form a vital source of fresh water. On the other hand, the aquifers being in hydraulic contact with sea are equally vulnerable to contamination due to intrusion of saltwater from the sea. The intrusion in these areas is caused by concentrated withdrawal of groundwater and reversal of natural hydraulic gradient. The problem has been reported in areas of Saurashtra, Tamilnadu, Andhra Pradesh and West Bengal.

It must be clearly understood that less than even 2% of sea water can diminish the water potability. The recommended remedial methods for salt water intrusion include modification of pumping pattern, artificial recharge, physical barrier and hydraulic barrier.

Groundwater Management Perspective

India's groundwater is not in a very good state. The annual recharge of water is far less than what is consumed. The situation is more alarming in urban areas due to population pressure and industrial growth. In spite of this, groundwater constitutes one vital component of water resource system and shall continue to play a key role in meeting the water needs. Hence it requires an integrated planning to optimally utilize, conserve and manage this precious resource. The concept of integrated approach for Groundwater management necessarily need to incorporate following aspects :

· Water conservation
· Watershed management
· Conjunctive use of surface and groundwater
· Augmentation of Groundwater by artificial recharge.


Apart from above, site- specific practices can also be highly purposeful and yield good results. Especially in coastal areas, increasing the direct use of brackish water combined with suitable crop pattern can reduce growing stress on fresh water. In Israel a similar exercise has yielded impressive results in case of cotton cultivation using brackish water for irrigation.