Analysing the factors influencing groundwater quality using the Leachate Pollution Index (LPI), Heavy Metal Pollution Index (HPI), and Partial Least Squares - Structural Equation Modelling (PLS-SEM) in the vicinity of an open dumping yard in Saduperi, Vellore, Tamil Nadu, India.

Abstract

Abstract Open dumping is the prevailing municipal solid waste (MSW) disposal technique in India. Unsanitary landfill system results in the release of leachate, a substance that has the potential to contaminate the nearby environment, including groundwater. Hence, the present study was carried out in the vicinity of the Saduperi open dumpsite, Vellore, Tamil Nadu, India, to explore the key factors that influence groundwater contamination. 18 sample wells were identified near the dumpsite and a total of 216 groundwater samples were collected between May 2021 and April 2022. These samples were categorized into four different seasons such as summer, southwest monsoon (SWM), northeast monsoon (NEM), and winter. The groundwater contamination is assessed using hydrogeochemical methods such as Piper and Gibbs diagrams. The leachate pollution index (LPI) and Heavy metal pollution index (HPI) were used to evaluate the contamination potential. The calculated LPI > 35 in all seasons indicates the prevailing poor environmental condition. It was observed that about 56% of the sampling site was affected by heavy metal concentrations such as Cd, Cr, and Ni. The HPI value was found to be more than the critical value of 100 in the 10 sampling wells for all seasons. Partial least squares-structural equation modelling (PLS-SEM) offers a novel approach to assessing the intricate link between several influencing elements and groundwater quality, in contrast to the conventional multivariate statistical technique. The PLS-SEM creates the link between Latent variables such as “IOT Parameters”, “Leachate Parameters”, “Heavy Metal” and “Groundwater Quality” which was quantified by the yield of R2 value. The R2 value of the sampling well ahead of the dumpsite and along the direction of the groundwater flow values ranging from 24.7–86.5% than the wells located behind the dumpsite are prone to get more contamination due to migration of leachate. Hence this present study shows various influencing factors that affect the groundwater quality.