Assessment of pollution in roadside soils by using multivariate statistical techniques and contamination indices

Pollution of roadside soils by heavy metals (HMs) presents serious concern throughout the world and, specifically, in India, due to the increasing traffic and anthropogenic activities. Understanding this problematic, policymakers and land managers will be able to design correct and sustainable land plans to avoid human health problems. The current study was conducted in order to determine the sources and levels of contamination by physiochemical parameters and HMs (Cu, Co, Cr and Pb) in roadside soils of Jalandhar, Punjab. A total of 90 samples were collected in triplicates from different sites and analysed for physiochemical and heavy metals. The average values of Cu, Co, Cr and Pb were found less than the permissible limits of Indian soils. Pearson’s correlation analysis indicated that HMs are positively correlated with each other, indicating a similar source of their origin. Further results of correlation analysis were supported by cluster analysis and Principal component analysis also indicated that HMs have the same source of origin mainly anthropogenic (agricultural and transportation activities), while soil properties have the same source of origin. The results of contamination factor, geo-accumulation index, potential contamination index, pollution index and ecological risk index showed that soils are moderately contaminated by HMs. In the future, further research would be needed to understand which specific factor (agriculture, industry and urban residues) could be considered as the main driving factor. We conclude that this study can provide the baseline data for policymakers and stakeholders to help the protection of soil ecosystem.