Evaluation of groundwater quality using linear regression model

The present study was undertaken to analyzed chemical parameters of groundwater samples were collected
from representative sampling stations established over entire study area in post monsoon 2005, and pre monsoon
2006 periods from 37 locations in parts of the Central Ganga Plain. Eight parameters such as, TDS, HCO3, Cl,
SO4, Na, K, Ca, and Mg were selected as the groundwater quality variables in this study. Total dissolved solids
(TDS) were calculated by summing up the concentrations of all the major cations and anions. The
concentrations of Ca++, Mg++, Cl-, HCO3
- and total hardness were determined by volumetric method. Ca++ and
Mg++ were determined by EDTA titration. For HCO3
-, HCl titration to a methyl orange point was used. Chloride
was determined by titration with AgNO3 solution. Flame emission photometry was used for the determination of
Na+ and K+. Sulphate was determined by gravimetric method. The higher values of TDS, Na, K, and Cl were
recorded in pre monsoon 2006 compared to post monsoon 2005. On the other hand the higher values of Ca, Mg,
HCO3, and SO4 were observed in post monsoon 2005 than pre monsoon 2006. This showed clear impact of land
use on groundwater. The regression analysis between TDS-Na; TDS-K; TDS –HCO3; showed strong positive
relationship as r = 0.802, 0.715, and 0.786 respectively, and moderate positive correlation with Cl ions (r=
0.579) and very low positive correlation (r= 0.055, 0.324 and 0.330) with Ca, Mg, and SO4. All the estimated
chemical parameter values were found to be statistically significant in both pre and post monsoon years.