BANGALORE: The hazardous chemicals present in groundwater in different parts of the State have breached all permissible limits.

Results obtained from the groundwater samples collected from 4,090 open dug-up wells and bore wells reveal that there is a large quantity of nitrate, fluoride and iron present in them.

A recent survey conducted by the Mines and Geology Department – Ground Water Resource Estimation Methodology – has revealed that groundwater is contaminated and there are excessive hazards, which prevail.

Groundwater forms about three per cent of the total available fresh water resource on earth. The ever-increasing demand for fresh water against limited potential has resulted in a stress on the fresh water resources.

The quality of groundwater is a major concern, and it comprises physical, chemical and bacteriological parameters-, which indicate the presence of disease-causing bacteria.

The chemical parameters reveal that there is excess nitrate. Ranging from a low of 46 milligram per litre (mg/l) in Adikemaranahalli village of Bangalore north taluk to a high value of 1183 mg/l in Neeramanvi village, Manvi Taluk and Raichur district. Limit of nitrate in drinking water is 45 mg/l.

Presence of fluorides reported in 21 districts range from 1.55 mg/l in Nandavedgi village, Hungund taluk, Bagalkot district to 10 mg/l in Jagatkal village, Deodurga taluk and Raichur district.

Total hardness ranges from 604 mg/l in Jigani village of Anekal taluk, Bangalore urban districts to 8920 mg/l in Haldipura village, Honnavar taluk and Uttar Kannada district. Excess iron ranges from 1.1 mg/l in Karwar, Haliyal, Mundgod and Siddapur taluks to 20 mg/l in Bhadavati town, Bhadravati taluk and Shimoga districts.

But the BIS recommend a permissible limit of 1.0 mg/l. Dr K Md Nazeeb, Scientist ‘D’, Central Ground Water Board, South Western Region told this paper that people should be encouraged to retain and recharge rain water back to the ground. ‘‘

Dilute hazardous chemicals and use it for drinking purposes. In urban areas roof water harvesting in rainy seasons is advisable. Due to urbanisation ground water is percolating’’.