Occurrence and distribution of selected potentially toxic elements in soils of playing sites: a case study from Bratislava, the capital of Slovakia

This study investigates the occurrence and distribution of potentially toxic elements (PTEs) (As, Cd, Cu, Hg, Pb and Zn) in soils collected at playing sites in kindergartens and urban parks in Bratislava city. It was found that the history of urban development was an important factor influencing the occurrence of PTEs in soils. The mean concentrations of PTEs were two times higher (mean of 215 mg/kg for the sum of PTEs) in the oldest urban parts than in urban parts of the city with younger history (mean of 110 mg/kg). Significant positive correlations between the concentrations of Cu, Hg, Pb, Zn and total organic carbon content (Spearman r = 0.23-0.49; alpha < 0.05-0.001), as well as between the As, Cu, Pb, Zn concentrations and the total Fe content (Spearman r = 0.27-0.55; alpha < 0.05-0.001) indicated that soil characteristics had also influenced the distributions of PTEs in soils. The values of enrichment factor (EF) and contamination factor (CF) were higher than 1.5 and 1.0, respectively, confirming an anthropogenic contribution to the total concentrations of PTEs in soils. It is expected that there is no non-carcinogenic health risk to children due to exposure to PTEs in soils as the calculated values of hazard quotient (HQ) and hazard index (HI) did not exceed the threshold of 1.0.