Magnetic susceptibility mapping of roadside pollution in the Banaras Hindu University campus, Varanasi, India

Among the several methods to determine anthropogenic pollutants in the soil, magnetic susceptibility measurements have proven to be useful for rapid and effective diagnosis of magnetic particles and overall screening of pollution. Magnetic particles and other heavy metals accumulated in the topsoil as a result of roadside pollution, contribute to the bulk magnetic susceptibility (chi). Thus, chi values of the soil can be utilized as a proxy to delineate the zones of high and low roadside pollution in an area. In this study, magnetic susceptibility measurements of the topsoil have been carried out and a quantitative assessment of roadside pollution in the Banaras Hindu University (BHU) campus, Varanasi, India is presented. Based on the chi values of 212 soil samples covering 1300 acres of the campus, zones of high and low roadside pollution are demarcated. The present study has not only deciphered the spatial variation of pollutants in the BHU campus, but has also characterized the magnetic phases responsible for the susceptibility signal on the roadsides inside the campus. The obtained results are crucial for environmental monitoring and prioritization of land use and other anthropogenic activities inside the BHU campus. The modus operandi adopted here would be beneficial for mapping areas exposed to different levels of pollution intensity, for tracing the pollution transport and can be effectively applied to various ecosystems.