Development of a water quality index (wqi) and application of multivariate statistical methods to assess the water quality of lower hooghly river,india : a case study

Abstract

Water Quality Index (WQI) is a valuable tool and gives single numeric expression to evaluate water quality and statistical analysis states the relationship between different parameters of water. To understand the changes in Physio-Chemical characteristics as per tidal variation were collected both in high tide and low tide from lower Hooghly River. After analysis it has been understood that due to high Salinity, TDS and EC water is not fit for uses in household and agricultural purposes and required proper treatment before using. In this study Hooghly River water quality studied thoroughly taken 10 (ten) sampling points in high tide and low tide starting from Geonkhali to Haldia dock under Purba Medinipur district at four (04) different season to assess the WQI. The main objective of this study is to know the Water Quality using WQI models and analysis of major cations and anions to understand there contribution in TDS and uses of river water in Agricultural, industrial and household purposes. From the value of Sodium absorption ratio (SAR), Sodium percentage (Na %), Kelly ratio (KR), Permeability Index (PI) value, Magnesium absorption ratio (MAR), and Potential salinity (PS) it can be stated that water is not fit for agricultural use. The value of Langelier Saturation Index (LSI) values indicates that unsuitable due to scale formation problems and Ryznar Stability Index (RSI) indicates that water is highly corrosive.Gibbs's diagram indicated that carbonate and silicate weathering significantly influence the lower Hooghly River ion chemistry and Piper trilinear diagrams indicated that Ca2+ and Mg2+ exceeded the Na+ and K +.The value of WQI analysis comes in the range of 400~ 2500 and it depicts that the lower Hooghly River is unsuitable for drinking purposes.