An assessment of urban habitat contamination with selected heavy metals within the city of Katowice using the common dandelion (Taraxacum officinale Web.) as a bioindicator

The common dandelion (Taraxacum officinale Web.) is considered to be a good indicator species due to its wide spread and high tolerance to harsh environmental conditions. It was used in this study to assess contamination with selected heavy metals (Zn, Pb, Cd) within urban habitats of the city of Katowice (southern Poland). Samples were collected from outside the forest regions. Content of heavy metals was determined using Flame Atomic Absorption Spectroscopy (F-AAS). The soil mineralization was conducted using 50,0 cm³ 10% HNO₃. Determination of elemental concentrations in the plant material was carried out with the “wet” method using heating blocks for a period of 7-10 days. The following concentration ranges for individual elements in soil were found: 14,03–2049,50 mg kg⁻¹ (Pb), 17,91–4118,00 mg kg⁻¹ (Zn), 0,25–52,93 mg kg⁻¹ (Cd). Concentrations within the leaves of common dandelion were: 5,52–93,04 μg g⁻¹ (Pb), 71,71–807,15 μg g⁻¹ (Zn), 0,10–15,69 μg g⁻¹ (Cd). Plants from the most heavily contaminated soils were characterised by the lowest bioaccumulation coefficient. The most contaminated areas were the districts: Szopienice-Burowiec and Wełnowiec-Józefowiec, while the least contaminated were the southern districts of Katowice (i.e. Zarzecze, Podlesie). There is also a clear link between the content of heavy metals in soils examined in this study and the land use.