Assessment of the level of pollution based on soil and Tilia × europaea leaves

Anthropic activities related to urbanization release pollutants, including potentially toxic elements, into the atmosphere and these are eventually deposited in soils, water, infrastructures, vegetation. Urban soil and plant leaves are widely used as ecological indicators to assess the effect of urbanization. This study aimed to evaluate the impact of urbanization based on the elemental concentration of soil and leaves of Tilia × europaea from urban, suburban, and rural areas along an urbanization gradient in Debrecen, Hungary. Using the ICP-OES technique, we measured the concentration of Ba, Cd, Co, Cr, Cu, Ni, Pb, Sr, and Zn and based on the measured concentration, bioaccumulation factor (BAF) was calculated. The highest concentration of all elements was found in soil samples from urban areas, with an increasing tendency along the urbanization gradient. A significant difference was found along the urbanization gradient only for Cr based on the plant leaves. T. × europaea showed bioaccumulation capacity for Cr and Sr. Our results suggest that urbanization has a remarkable effect on the elemental concentration of soil, which is a perfect ecological indicator. At the same time, we concluded that the T. × europaea was not sensitive enough to indicate the effect of urbanization. ### Competing Interest Statement The authors have declared no competing interest.