Soil heavy metals contamination and ecological risk assessment in Rohtak urban area, Haryana (India)

Soil contamination by various heavy metals is a significant global environmental problem. The problem is more severe in the rapidly industrializing and developing countries like India, posing significant health risks. This study was undertaken to measure heavy metals contamination of soil in industrial clusters developed by Haryana State Industrial and Infrastructure Development Corporation (HSIIDC) and various traffic junctions of Rohtak City. Risk assessment and characterization of heavy metals in soil was carried out using contamination factor (CF), pollution load index (PLI), and potential ecological risk index (RI). A total of 32 soil samples were collected from various locations and heavy metals were analyzed using atomic absorption spectrophotometer (AAS). The average value of heavy metals like Cd, Fe, Zn, Ni, and Cr in soil was 7.54 ± 5.89, 209.80 ± 137.44, 127.39 ± 80.43, 21.57 ± 24.02, and 17.05 ± 10.73 mg/kg, respectively. The mean values of contamination factor (CF) for Cd, Zn, Ni, Cr, and Fe were 37.68, 1.00, 0.44, 0.24, and 0.005, respectively. The values of the potential ecological risk index (RI) were 1130.4, 2.20, 1.00, and 0.48 for Cd, Cr, Zn, and Ni, respectively. Cadmium (Cd) presented the highest ecological risk index in comparison to other heavy metals. The mean geo-accumulation (Igeo) indices for heavy metals were ranked as follows: Cd > Zn > Ni > Cr > Fe. Principal component analysis (PCA) showed that 78.27% variation was caused by the first five principal components (PCs). The interpolation of spatial distributions of soil heavy metals highlighted that contamination values for most metals increased towards the western side of the city. The present study reveals that a higher concentration of cadmium was found in soils of Rohtak urban area. It could be due to the presence of metal processing and plating industries in the surveyed area and a lack of strict industrial norms.