Chemical Composition and Contamination of Nitrate and Fluoride in Groundwater of Alipur Block in Delhi State

A study was carried out to find out the chemical composition and contamination of nitrate and fluoride in groundwater of different villages of Alipur block in Delhi State during 2007. The groundwater samples were collected during pre and post-monsoon seasons (May and October, 2007) from 20 selected villages in Alipur block of Delhi State. Results indicated that quality of groundwater samples in terms of total soluble salts (EC_iw) was in the range of 0.46–5.80 dS m⁻¹. Based on the relative dominance of different cations and anions, the groundwater was classified as Na-Mg-Ca and Cl-HCO₃-SO₄ type having sodium and chloride more than 60% of the total salt constituents. Nitrate-nitrogen in groundwater samples during pre and post-monsoon season ranged from 0.90 to 11.80 mg L⁻¹ and 0.80 to 11.70 mg L⁻¹ with mean value of 3.81 mg L⁻¹ and 3.71 mg L⁻¹ and fluoride concentration ranged from 0.14 to 4.19 mg L⁻¹ and 0.12 to 4.18 mg L⁻¹ with mean values of 1.52 and 1.50 mg L⁻¹, respectively. Nitrate- nitrogen concentration of groundwater in Alipur village was found higher than permissible limit (10 mg L⁻¹) and fluoride concentration more than permissible limit (1.5 ppm) was observed in Kheda khurd, Alipur, Jagatpur, Shampur and Wazirabad villages of the block. The higher concentrations of salinity, sodicity, nitrate and fluoride in groundwater having adverse effect on plant growth and also causes the serious health problems to human beings. The higher concentrations of salinity and sodicity reduces the yield of the crops and the concentration of nitrate-N more than 10 mg/l and fluoride more than 1.5 mg/l in groundwater causes the Methemoglobinemia or Blue Baby Syndrome and Fluorosis diseases in human as well as in animals, respectively.