Evaluation of Potentially Toxic Element Contamination and Related Health Risk Assessment in Soil of Odisha, India

The Geological Survey of India (GSI) conducted an extensive geochemical survey under the National Geochemical Mapping (NGCM) project in Odisha, analysing 28,115 stream sediment samples. This study focused on 10 potentially toxic elements (Co, Cu, Cd, Cr, Zn, W, As, Mn, Ni, and V) from a dataset of 51 elements to evaluate soil contamination across the state. Multivariate statistical techniques revealed significant inter-element relationships, while Geographic Information System (GIS) methods were employed to generate interpolated geochemical distribution maps. The study identified a concentration hierarchy of Cr > Mn > V > Zn > Ni > Cu > Co > Cd > As > W among the elements, with Spearman correlation analysis indicating strong associations among Cd and W. Soil contamination levels were evaluated using pollution indices such as the geo-accumulation index (Igeo), contamination factor (CF), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI). The results revealed moderate to high pollution levels in Odisha's northern and southwestern regions, primarily driven by Cd, W, Cr, and Ni. Principal Component Analysis (PCA) identifies four significant components in the dataset, with distinct contributions from various elements. PC1, accounting for the largest variance, is primarily influenced by Cd (17%), Cr (16%), and Ni (14%), suggesting a strong association with ultramafic geological sources, sulfide mineralization, or to some extent industrial pollution. In contrast, PC2 is dominated by Co (26%), Mn (23%), Cu (21%), and Zn (18%), which are often linked to metalliferous inputs, soil geochemistry, and anthropogenic activities such as mining and industrial discharge. Health risk assessment showed children were more vulnerable to Co, Cr, V, As and Cd toxicity in the study region. Whereas, Cd, Cr, and Co are major risk contributors for adult males and females. The hazards associated with non-carcinogenic and carcinogenic soil metals exceeded tolerable thresholds. The computed Hazard Index indicates that soil particle ingestion is the primary exposure pathway associated with elevated risk, succeeded by dermal contact. The results endorse the formulation of targeted remediation plans and policies to mitigate health concerns linked to these polluted soils.