Influence of different types of land use on the contents of potentially toxic elements and de-icing salts in roadside soils and trees in urban areas

Abstract

In order to manage the urban environment and reduce pollution, it is essential to determine potentially toxic elements and de-icing salts in roadside soils and plants, which are major components of green infrastructure. A field study was conducted to elucidate the influence of land use on potentially toxic elements and deicing salts in roadside soil and trees in urban areas. The effect of land use was determined in commercial, residential, industrial, and green areas of Cheongju city. The roadside soil and plant samples were collected from four different sites along a major roadway in the city. The chemical parameters determined were pH, electronic conductivity, potentially toxic elements (Cd, Cu, Zn, Cr, As, Pb, Ni), and de-icing salts (Na, Ca, Mg). The pH, electronic conductivity, potentially toxic elements (except copper), and deicing salt values were significantly (p < 0.05) affected by the land use. On the other hand, the heavy metal (except zinc and nickel) levels in roadside tree leaves (Ginkgo biloba) were not affected by the different land use, whereas the deicing salt levels were significantly different (p < 0.05). The enrichment factor (EF) of potentially toxic elements was found to be lower than that of de-icing salts with the highest values of sodium in green areas and of magnesium in commercial areas. These results provide information on the implications of land use, including the surrounding area of influenced roadside soil and plant chemistry for the urban ecosystem.