Variations in the zinc and lead content in surface layers of urban soils in Kielce (Poland) with regard to land use

The article presents an overview of the results of a study concerning the zinc and lead content in urban soils of Kielce with regard to different land use. 61 topsoil samples were collected in the industrial areas (I), urban green areas (Z), urban allotment gardens (O), as well as parks and forests (P). The maximum values for zinc and lead were observed in the industrial zone, i.e. 181.3 mg kg-1 and 112.6 mg kg-1, respectively; whereas the average content in the soils of Kielce oscillates at the level of 134.2 mg kg-1 for zinc and 92.85 mg kg-1 for lead. Geochemical indices, such as the geoaccumulation index (Igeo), contamination factor (CF) and accumulation index (AI) indicated that areas located in close proximity to the main roads of the city, especially in the city centre and the former industrial estate called Białogon, are characterised by the highest concentration of the analysed heavy metals. Generally, the enrichment of soils in zinc and lead decreases further from the city centre. In most cases, the content of the analysed heavy metals in surface layers of urban soils considerably exceeded values considered as geochemical background and valid legal norms of the Ordinance of the Minister of Environment on soil quality standards and land quality standards (Journal of Laws of 2002, No. 165, item 1359). The exceeded values of the analysed metals are caused mainly by deposition of contamination from car exhaust emissions and broadly defined industry.