Bioaccumulation of copper, lead and zinc by Taraxacum officinale agg. growing on urban soils of different land-use types

Common dandelion Taraxacum officinale agg. (T. officinale F.H. Wigg) is a plant species commonly found on urban areas. It is characterised by low habitat requirements and proven bioindication properties. The aim of this study was to assess the possibility of using T. officinale agg. for monitoring of the urban soils in the City of Kielce with regard to selected heavy metal concentrations, i.e. Pb, Cu and Zn. Twenty-one soil and dandelion samples (roots and leaves) were collected from the area of Kielce. The study areas were designated with regard to land-use types, i.e. industrial areas, urban parks and forests, urban green areas, and urban allotment gardens. The total heavy metal concentrations were determined in the soil and plant material by the ICP-AES (inductively coupled plasma atomic emission spectroscopy) method, after mineralisation of the samples in a mixture of HCl-HNO3 (3:1). Moreover, the soil samples were analysed in terms of pH values. The concentrations of heavy metals in the analysed soils were oscillating at: 16.5-290 mg/kg d.m. for Pb; 7.11- 41mg/kg d.m. for Cu; 55.7-338 mg/kg d.m. for Zn In the case of dandelion leaves, the concentration range was recorded at: 1.07-3.11 mg/kg d.m. for Pb; 3.11-14.1 mg/kg d.m. for Cu; 19.7-121 mg/kg d.m. for Zn. Regarding the dandelion roots, the concentration range was as follows: 0.54-2.09 mg/kg d.m. for Pb; 2.89-8.11 mg/kg d.m. for Cu; 15.8-67.1 mg/kg d.m. for Zn. The study indicated that the concentrations of analysed heavy metals adopted the sequence of soil>leaves>root. The above relationship may indicate a significant impact of heavy metals contained in the air on their concentrations in the upper parts of plants. The pH of analysed soils were oscillating at 3.99-7.92 and was not correlated with the concentrations of heavy metals in the soils. Heavy metal concentrations were not significantly affected by the land-use types, which may indicate that urban pollution emission zones are not limited only to industrial and transportation areas.