A Multi-Year Assessment of Soil Physicochemical Properties, Major and Trace Metal Contamination Near a Cement Plant in Karbi Anglong, Assam, India

Abstract

This study presents a multi-year (2022–2024) investigation into the soil physicochemical properties and contamination by major and trace metals around a cement plant in Karbi Anglong, Assam, India. Soil samples collected from four directional zones during 2022–2024 were analyzed for pH, electrical conductivity (EC), organic carbon (OC), major elements (Mg, Ca, Na, K, P), and trace metals (As, Cr, Cu, Pb), and the data were assessed using statistical techniques, and contamination indices. The results indicated that soils exhibited neutral to moderately alkaline conditions (pH 7.24–8.39), with low to moderate EC and OC levels falling within the optimal range for agricultural use, suggesting generally favourable physicochemical conditions. Statistical analyses, including Pearson correlation and Principal Component Analysis (PCA), revealed strong associations among several trace metals (Cr, Cu, Pb), indicating a common anthropogenic origin linked to cement plant emissions.  One-way ANOVA showed statistically significant spatio-temporal variations, primarily for EC and As. The Contamination Factor (CF) pointed from low to moderate contamination for arsenic and chromium, and low contamination for copper and lead. The Pollution Load Index (PLI) remained below unity across all sites and years, signifying overall unpolluted baseline conditions. In conclusion, while the soils in the study area are largely suitable for agriculture, the localized enrichment of As and Cr highlights the need for continuous monitoring. These findings provide critical baseline data to mitigate potential long-term environmental and human health risks associated with cement industry emissions in the region.