Pollution Research Paper

QUALITY EVALUATION AND IRRIGATIONAL SUITABILITY OF GROUNDWATER OF CHITTUR BLOCK, PALGHAT, KERALA, INDIA

T.R. DEEPU AND E. SHAJI

Abstract

Groundwater is the most important source of domestic, industrial and agricultural water supply in the world. Suitability of water for various uses depends on type and concentration of dissolved minerals. Geochemical characteristics of groundwater in the weathered crystalline terrain of Chittur block, Palghat was evaluated during the pre-monsoon (April, 2016) for to assess its appropriateness for domestic and irrigational purposes. Fifty nine groundwater samples were collected and analysed for pH, EC, TDS and all major cations and anions. Chemical analysis of the groundwater shows different ranges for different parameters (pH 6.1-8.2, EC 380-1750 S/cm, TDS 243-1120 mg/L, TH 90-510 mg/L, Ca2+ 6.01-142.28 mg/L, Mg2+ 5.9-103.23 mg/L, Cl- 50-452 mg/L, Na+ 29-147 mg/L, K+ 0-61 mg/L, NO3- 0.003-0.189 mg/L, SO4 2- 2.7-128.4 mg/L and PO4 - 0.1-8.1 mg/L). The groundwater sample beyond the acceptable limit of EC, TDS, TH, Ca2+, Mg2+, Cl- and PO4 3 – are not suitable for domestic use. Irrigational suitability of water for irrigation is evaluated based on sodium adsorption ratio (SAR) , residual sodium carbonate (RSC), Kelly’s ratio (KR), sodium percent (%Na), magnesium hazard (MH), salinity hazard and USSL diagram. The percent sodium ranges from 23.92- 68.12, good to doubtful category for irrigation. KR ranges from 0.31- 2.09, the value of KR less than one are suitable for irrigation, while those with ratio more than one are unsuitable. SAR values ranges from 0.92 to 5.16, all samples fall in the excellent category. RSC values of all samples are less than 1.25 epm and are safe for irrigation. Magnesium hazard ranges from 6.47-93.12, MH > 50 is considered harmful and unsuitable for irrigation purpose. US salinity hazard reveals that 30 samples falls under C3S1 (high salinity hazard and low sodium. The groundwater observed from high salinity water (C3) is considered to be moderate quality to irrigate semi-tolerant crops.