Comparative study of water quality between upstream and downstream of Thamirabarani River using multivariate statistical tools

Abstract

The present investigations were focused on the systematic analysis of surface water quality of the Thamirabarani River from upstream (Pechiparai dam to Gnaramvilai) to downstream (Vettuvenni to Thengaipattinam estuary) during the period from September 2020 to January 2021. The different hydrochemical parameters such as temperature, pH, EC, TDS, fluoride, turbidity, nitrate, phosphate, sulphate, chloride, calcium, magnesium, total hardness, DO, BOD, bicarbonate, carbonate, sodium and potassium were determined upstream (S1-S5) and downstream (S6-S10) of the river water samples. The results showed that the weighted Arithmetic Water Quality Index (WAWQI) values designated two sampling stations out of ten sampling stations ‘Good’ category and another eight sampling stations ‘poor - unsuitable’ category. The results obtained were subjected to multivariate statistical analysis using Correlation matrix the significant relationship among the parameters (significance level with 0.01 and 0.05) PCA and Cluster was also calculated to determine the high pollution loads in the water sample. The mean values of the respective major ions determined are represented in the Schoeller- Berkaloff diagram. From this study the water quality was severely polluted both upstream and downstream region the water quality index and multivariate techniques can be employed for monitoring river resources which can help inadequate planning and management of the Thamirabarani river system. Key words: Correlation analysis, cluster analysis, hydrochemical parameters, principal component analysis, statistical analysis, water quality index.