Potential Ecological Risk Assessment of Ni, Cu, Zn, Cd, and Pb in Roadside Soils

The present study seeks to both estimate and analyze the rate of heavy metal changes in soils of road margins affected by the traffic on Fasa-Darab Road, Iran. Muller index, contamination factor (CF), Geoaccumulation index (I-geo), potential ecological risk index (PERI), and pollution load index (PLI) were calculated to determine the contamination rate. Principal component analysis was also employed to determine the most relevant parameters affecting the PERI. The maximum amount of heavy metal contamination (2.5 mg/kg) occurred at the nearest road distance, that is, 2 m. The results of the I-geo show that these elements are naturally present in the soil, albeit anthropogenic activity caused an increase in the concentration of these metals in soil. Results of the CF index showed that Ni, Cu, and Zn values were less than 1, indicative of low contamination, whereas Pb contamination, with values ranging from 3 to 6 was indicative of high pollution. The PLI results for the most polluted stations showed that stations 14 and 23 were classified as very high contamination and other stations as uncontaminated. The results of clustering data showed that the data were in two pollution classes. As maintained by the findings, the first component contributed to 44.98% of the changes and included the Cd, CFCd, RI, and I-geo(Cd) parameters, while the second component represented 27.83% of the changes, containing parameters Pb, I-geo(Pb), and CFPb. Therefore, Pb and Cd are the most relevant parameters in the analysis of PERI within the study area.