Exploring the impact of transportation on heavy metal pollution: A comparative study of trains and cars

This study aimed to investigate the impact of road and rail traffic on the soil through the analysis of the presence of heavy metals in soil samples collected next to a busy highway, local roads, and next to an active railway line. Results showed that cars emitted higher levels of heavy metals than trains. Soil samples near the highway had higher levels of Cu, Ni, and Hg. The values of the calculated indices like geo-accumulation index, potential toxicity response index, ecological risk factor, contamination factor, pollution load index, Nemerow's pollution index, and degree of contamination confirm that the soil samples sampled near the highway are the most polluted and highway have the greatest negative impact on the soil environment. These results suggest that controlling car emissions through strict regulations and promoting public transportation could effectively reduce the heavy metal concentrations in soil, particularly from highway emissions.