Assessment of leachate potential contamination of municipal landfill using leachate pollution index and multivariate statistical analysis based on seasonal variations

Sanitary landfills offer a convenient and cost-effective way to dispose of MSW waste. The breakdown of waste in landfills generates highly poisonous leachate. This liquid can disperse and percolate through the soil, potentially polluting the surrounding water bodies; minimizing the environmental damage caused by leachate lies in thoroughly understanding its unique characteristics at each landfill site. The present study evaluates the leachate's physio-chemical characteristics from municipal landfills and adjacent groundwater sources. To evaluate the impact of temporal seasonal fluctuation, leachate and water samples were collected in three distinct seasons such as pre-monsoon (Pre-M), monsoon (In-M), and post-monsoon (Post-M). The analysis revealed a seasonal variation in pollution levels in the leachate sample, as evidenced by the high Leachate Pollution Index (LPI) spanning 27.121–17.396. Water samples collected across three seasons yielded Water Quality Index (WQI) values ranging from 55.59 to 279.64, with the Pre-M season exhibiting the highest level of water quality. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis were employed to understand the elemental composition further. The presence of heavy metals Zn, Cr, Cu, Ni, Fe, Si, and Hg was determined combined through the Inductive Coupled Plasma Atomic Emission Spectroscopy technique and EDX. The correlation matrix heat map helped to reveal the interconnection between different leachate parameters, and dendrogram clusters revealed the relation between the six sampling points. At the same time, Principal component analysis was performed to simplify the complex data set and determine the predominance of pollutants over the sample points. As explored in this study, understanding the contamination potential of landfill leachate is crucial for developing strategies before its disposal to mitigate its impact.