Groundwater contaminated in Gulbarga District

THE HINDU, [24 June, 2002]

GULBARGA June 23. A study on the quality of drinking water in borewells in 25 localities in Gulbarga city and a few selected villages in Gulbarga District by the Environmental Biology Research Unit of the Zoology Department in Gulbarga University has come out with shocking results of high concentration of nitrate, total hardness, and presence of coliforms in some of the locations.

The two year study conducted by the Reader in Zoology Department, K.Vijaykmar, and the research scholar, I.Ramesha, from the samples collected from these sources in different seasons have come to a conclusion that the presence of high concentration of nitrate, and coliforms were because of the unscientific disposal of human, animal, and municipal waste.

Poorly-designed septic tanks, soak pits, and open pit latrines were the major anthropogenic sources of nitrate contamination and high deposit of bacteria, virus, ammonia, and chlorides in samples. The study revealed that another source of nitrate pollution in groundwater was the indiscriminate application of nitrogen fertilizer in the agriculture fields. The tests revealed that the nitrate level was high in groundwater during winter. The study pointed out that the high nitrate contamination of drinking water, primarily the groundwater and wells, due to its methemoglobinema would expose the people to the risks of developing stomach and gastrointestinal cancer and other diseases. Dr. Vijaykumar told The Hindu here on Sunday that the study conducted by the team proved that the nitrate concentration varied between 105 mg. per litre to 416 mg. per litre in Gulbarga city and 98 mg. per litre in Kamalapur, 163 mg. per litre in Hebbal. However, all water samples were above permissible limits, except during summer. The permissible limit of nitrate concentration as per the Indian standard was 45 mg. per litre. Another interesting discovery made during the investigation was that the concentration of nitrate was high in the drinking water sources during North-East monsoon and south-west monsoon, indicating the high use of nitrogen-based fertilizers in the adjacent agriculture fields.

Dr. Vijaykumar said that although some work had been done to study groundwater quality studies in India, it was difficult due to variation in geology, which would have significant impact or the variation in water quality.

To overcome this problem, the present study was conducted for two years to know the physical, chemical, and bacteriological analysis of the samples collected in Gulbarga city and five selected villages. The study covered bore wells located at Omnagar, S.B.Temple, Sangameshwar Colony, Vittal Nagar, C.P.Nagar, Railway Station, NGO's Colony, Okaly Camp, Jayanagar, Basaveshwar Colony, Ambedkar Hostel, Anand Nagar, Jagat, Super Market, Shahabazar, M.S.K.Mill, Shanti Nagar, Bhagavati Nagar, Tarpail, Jail, Venkateshwar Colony, CBI Colony Darga, Gunj, and Revanasiddeshwar Colony. The studies were conducted on quality of water in borewells in Jewargi, Sulepet, Hebbal, Kamalapur, and Sedam. The study revealed that only six borewells in the city Omnagar, S.B.Temple, Sangameshwar Colony, Vittal Nagar, C.P.Nagar, and Railway Station were within the permissible limits of electrical conductivity and the remaining 18 borewell samples were found to be saline and one at NGO's Colony was brackish and unfit for human consumption. Most borewells where the samples were drawn for conducting tests to ascertain the presence of total dissolved solids (TDS) showed that the water was unfit for human consumption and was fit only for agriculture. Similarly, samples drawn from all borewells in the city and rural areas showed the presence of hard water.

Dr. Vijaykumar said the authorities should take immediate measures to prevent the contamination of borewells by removing the septic tanks to a safer distance of at least 10 meters from the groundwater source. The authorities should use zeolite to control the contamination of water and the nitrate in the water should be treated through demineralisation methods and distillation.

He said that there was an urgent need for taking up quality studies in all parameters of all drinking water sources in the city and the university was ready to take up the study provided necessary financial assistance was given.